GetWiki

{{Short description|none}}{{Redirect|Westward expansion|trails in the American Old West|Westward Expansion Trails}}File:United States evolution small.gif|350px|thumb|right|Animated map of the territorial evolution of the United States ((:File:United States evolution.gif|click to view full size image))]](File:Aquired Lands of the US.svg|thumb|US Census Bureau map depicting territorial acquisitions, 2007)File:NOAA Map of the US EEZ.svg|thumb|After Japan’s defeat in World War II, the Japanese-ruled Northern Mariana IslandsNorthern Mariana IslandsThe United States of America was formed after thirteen British colonies in North America declared independence from the British Empire on July 4, 1776. In the Lee Resolution, passed by the Second Continental Congress two days prior, the colonies resolved that they were free and independent states. The union was formalized in the Articles of Confederation, which came into force on March 1, 1781, after being ratified by all 13 states. Their independence was recognized by Great Britain in the Treaty of Paris of 1783, which concluded the American Revolutionary War. This effectively doubled the size of the colonies, now able to stretch west past the Proclamation Line to the Mississippi River. This land was organized into territories and then states, though there remained some conflict with the sea-to-sea grants claimed by some of the original colonies. In time, these grants were ceded to the federal government.The first great expansion of the country came with the Louisiana Purchase of 1803, which doubled the country’s territory, although the southeastern border with Spanish Florida was the subject of much dispute until it and Spanish claims to the Oregon Country were ceded to the US in 1821. The Oregon Country gave the United States access to the Pacific Ocean, though it was shared for a time with the United Kingdom. The annexation of the Republic of Texas in 1845 led directly to the Mexican–American War, after which the victorious United States obtained the northern half of Mexico’s territory, including what was quickly made the state of California. As the development of the country moved west, however, the question of slavery became more important, with vigorous debate over whether the new territories would allow slavery and events such as the Missouri Compromise and Bleeding Kansas. This came to a head in 1860 and 1861, when the governments of the southern states proclaimed their secession from the country and formed the Confederate States of America. The American Civil War led to the defeat of the Confederacy in 1865 and the eventual readmission of the states to the United States Congress. The cultural endeavor and pursuit of manifest destiny provided a strong impetus for westward expansion in the 19th century.The United States began expanding beyond North America in 1856 with the passage of the Guano Islands Act, causing many small and uninhabited, but economically important, islands in the Caribbean Sea and the Pacific Ocean to be claimed. Most of these claims were eventually abandoned, largely because of competing claims from other countries. The Pacific expansion culminated in the annexation of Hawaii in 1898, after the overthrow of its government five years previously. Alaska, the last major acquisition in North America, was purchased from Russia in 1867. Support for the independence of Cuba from the Spanish Empire, and the sinking of the USS Maine, led to the Spanish–American War in 1898, in which the United States gained Puerto Rico, Guam, and the Philippines, and occupied Cuba for several years. American Samoa was acquired by the United States in 1900 after the end of the Second Samoan Civil War.Ryden, George Herbert. The Foreign Policy of the United States in Relation to Samoa. New York: Octagon Books, 1975. The United States purchased the U.S. Virgin Islands from Denmark in 1917www.vinow.com/general_usvi/history/ Vinow.com. Virgin Islands History. Retrieved January 18, 2018. Puerto Rico and Guam remain territories, and the Philippines became independent in 1946, after being a major theater of World War II. Following the war, many islands were entrusted to the U.S. by the United Nations, and while the Northern Mariana Islands became a U.S. territory, the Marshall Islands, Federated States of Micronesia, and Palau emerged from the trust territory as independent nations. The last major international change was the acquisition in 1904, and return to Panama in 1979, of the Panama Canal Zone, an unincorporated US territory which controlled the Panama Canal. The final cession of formal control over the region was made to Panama in 1999.States have generally retained their initial borders once established. Only three states (Kentucky, Maine, and West Virginia) have been created directly from area belonging to another state (although at the time of admission, Vermont agreed to a monetary payment for New York to relinquish its claim); all of the other states were created from federal territories or from acquisitions. Four states (Louisiana, Missouri, Nevada, and Pennsylvania) have expanded substantially by acquiring additional federal territory after their initial admission to the Union. In 1912, Arizona was the last state established in the contiguous United States, commonly called the “lower 48”. In 1959, Hawaii was the 50th and most recent state admitted.

Legend for maps

“>

1776–1784 (American Revolution){|class“wikitable plainrowheaders”

!scope=“col“|Date!scope=“col“|Event!scope=“col“|Change Map!scope=row|July 4, 1776

Thirteen Colonies>Thirteen colonies of the Kingdom of Great Britain in North America collectively United States Declaration of Independence	as the United States of America,{{efn>The borders of the country followed the colonial borders; for simplicity, the maps use the borders defined in the 1783 Treaty of Paris (1783)	. The only substantive difference between the borders before and after the Treaty of Paris is the southwest border: when Great Britain had ownership over West Florida, they had moved its border north, to a line east from the mouth of the Yazoo River, and that area thus did not belong to Georgia; the treaty granted the area between this and 31st parallel north>31° north to the United States.}} though several colonies had already individually declared independence:HTTPS://WWW.ARCHIVES.GOV/FOUNDING-DOCS/DECLARATION-TRANSCRIPT >TITLE=DECLARATION OF INDEPENDENCE: A TRANSCRIPTION	PUBLISHER=NATIONAL ARCHIVES AND RECORDS ADMINISTRATION, September 7, 2017, The Colony of Connecticut, becoming the State of ConnecticutVan Zandt, pp. 72–74 The Counties of New Castle, Kent, and Sussex, upon Delaware, commonly known as the Lower Counties on Delaware, which was Delaware Colony before their declaration of independence on June 15, 1776Van Zandt, pp. 84–85WEB,delaware.gov/topics/facts/gov.shtml, Delaware Government Facts & Symbols, Government of Delaware, January 16, 2017, live,web.archive.org/web/20170109144723/https://delaware.gov/topics/facts/gov.shtml, January 9, 2017, The Province of Georgia, becoming the State of GeorgiaVan Zandt, pp. 100–104 The Province of Maryland, becoming the State of MarylandVan Zandt, pp. 85–88 The Province of Massachusetts Bay, becoming the State of Massachusetts BayVan Zandt, pp. 65–71 The State of New Hampshire, which was the Province of New Hampshire before their declaration of independence on June 15, 1776Van Zandt, pp. 60–64BOOK,books.google.com/books?id=AYk0AQAAMAAJ, The Laws of the State of New Hampshire, 1824, 239–240, January 16, 2017, Hampshire, New, The Province of New Jersey, becoming the State of New JerseyVan Zandt, pp. 79–80 The Province of New York, becoming the State of New YorkVan Zandt, pp. 74–79 The Province of North Carolina, becoming the State of North Carolina;Van Zandt, pp. 96–99 some believe the colony declared independence on May 20, 1775, but this is disputed The Province of Pennsylvania, becoming the State of PennsylvaniaVan Zandt, pp. 80–84 The State of Rhode Island and Providence Plantations, commonly known as Rhode Island, which was the Colony of Rhode Island and Providence Plantations before declaring independence on May 4, 1776Van Zandt, pp. 71–72WEB,www.history.com/this-day-in-history/rhode-island-declares-independence, Rhode Island declares independence, History Channel, January 16, 2017, live,www.history.com/this-day-in-history/rhode-island-declares-independence," title="web.archive.org/web/20170118033158www.history.com/this-day-in-history/rhode-island-declares-independence,">web.archive.org/web/20170118033158www.history.com/this-day-in-history/rhode-island-declares-independence, January 18, 2017, The Province of South Carolina, becoming the State of South CarolinaVan Zandt, pp. 99–100 The Colony of Virginia, becoming the Commonwealth of VirginiaVan Zandt, pp. 92–95 The capital was not specifically established; at the time, the Continental Congress met in Philadelphia.WEB,www.senate.gov/reference/reference_item/Nine_Capitals_of_the_United_States.htm, Nine Capitals of the United States, U.S. Senate, March 19, 2016,web.archive.org/web/20160320084755/https://www.senate.gov/reference/reference_item/Nine_Capitals_of_the_United_States.htm, March 20, 2016, WEB,www.history.com/news/8-forgotten-capitals-of-the-united-states, 8 Forgotten Capitals of the United States, History (U.S. TV channel), History, March 12, 2017, live,www.history.com/news/8-forgotten-capitals-of-the-united-states," title="web.archive.org/web/20170126151622www.history.com/news/8-forgotten-capitals-of-the-united-states,">web.archive.org/web/20170126151622www.history.com/news/8-forgotten-capitals-of-the-united-states, January 26, 2017, Many states had vaguely defined and surveyed borders; these are not noted as contested in the maps unless there was an active dispute. The borders of North Carolina were particularly poorly surveyed, its border with South Carolina having been done in several pieces, none of which truly matched the spirit of the charter,WEB,www.carolana.com/Carolina/Noteworthy_Events/NC_SC_border_surveys.html, The North Carolina – South Carolina Border Surveys – 1730 to 1815, December 30, 2015, live,www.carolana.com/Carolina/Noteworthy_Events/NC_SC_border_surveys.html," title="web.archive.org/web/20160304054336www.carolana.com/Carolina/Noteworthy_Events/NC_SC_border_surveys.html,">web.archive.org/web/20160304054336www.carolana.com/Carolina/Noteworthy_Events/NC_SC_border_surveys.html, March 4, 2016, NEWS,www.nytimes.com/2014/08/24/opinion/sunday/how-the-carolinas-fixed-their-blurred-lines.html?_r=0, How the Carolinas Fixed Their Blurred Lines, The New York Times, Kelly, Stephen R., August 23, 2014, December 30, 2015, live,www.nytimes.com/2014/08/24/opinion/sunday/how-the-carolinas-fixed-their-blurred-lines.html?_r=0," title="web.archive.org/web/20140831014105www.nytimes.com/2014/08/24/opinion/sunday/how-the-carolinas-fixed-their-blurred-lines.html?_r=0,">web.archive.org/web/20140831014105www.nytimes.com/2014/08/24/opinion/sunday/how-the-carolinas-fixed-their-blurred-lines.html?_r=0, August 31, 2014, and its border with Virginia was only surveyed roughly halfway inland from the sea.Several northeastern states had overlapping claims: Connecticut, Massachusetts Bay, and New York all claimed land west of their accepted borders, overlapping with each other and with a sizable claim by Virginia. Of the three, only Connecticut seriously pursued its claims, while Virginia is considered to have had the most legitimate claim to the vast northwest, dividing it into counties and maintaining some limited control.The entirety of the new United States was claimed by Great Britain, including Machias Seal Island and North Rock, two small islands off the northeast coast which remain disputed up to the present.NEWS,nationalpost.com/news/canada/a-haven-for-puffins-tranquil-island-off-nova-scotia-is-a-rare-piece-of-disputed-territory-between-canada-and-the-u-s, Puffin Wars: The island paradise at centre of last Canada-U.S. land dispute, National Post, O’Connor, Joe, November 27, 2012, April 1, 2019,	(File:United States Central change 1776-07-04.png	250px)Disputes:(File:United States Central disputes 1776-07-04 to 1777-01-15.png|alt=Map of the international disputes involving the United States in central North America from July 4, 1776, to January 15, 1777|250px)

!scope=row|September 20, 1776

Delaware Constitution of 1776>constitution, renaming itself Delaware	.HTTP://AVALON.LAW.YALE.EDU/18TH_CENTURY/DE02.ASP	YEAR=1776	YALE LAW SCHOOL >WORK=AVALON PROJECT	URL-STATUS=LIVE	ARCHIVE-DATE=JULY 9, 2009,	(File:United States Central change 1776-09-20.png	250px)

!scope=row|September 28, 1776

Pennsylvania Constitution of 1776>constitution, renaming itself the Pennsylvania	.HTTP://AVALON.LAW.YALE.EDU/18TH_CENTURY/PA08.ASP	YEAR=1776	YALE LAW SCHOOL >WORK=AVALON PROJECT	URL-STATUS=LIVE	ARCHIVE-DATE=JANUARY 26, 2017,	no change to map

!scope=row|December 20, 1776

Kingdom of Great Britain>British forces who were advancing on Philadelphia, the Continental Congress began meeting in Baltimore.	(File:United States Central change 1776-12-20.png	250px)

!scope=row|January 15, 1777

New York (state)>New York, known as the New Hampshire Grants, declared independence as Vermont Republic	.HTTPS://ARCHIVE.ORG/DETAILS/PROVINCIALANDST01COURGOOG	YEAR=1877	PAGES=242–246	FIRST1=NEW HAMPSHIRE (COLONY) PROBATE, Vermont 2006 J.R.H. 3, Joint Resolution Designating January as Vermont History and Independence Month {{webarchive	www.leg.state.vt.us/docs/legdoc.cfm?URL=%2Fdocs%2F2006%2Facts%2FACTR105.HTM >date=October 11, 2006 }}	Disputes:(File:United States Central dispute change 1777-01-15.png|alt=Map of the change to the international disputes involving the United States in central North America on January 15, 1777|250px)

!scope=row|March 4, 1777

Continental Congress returned to Philadelphia after the threat to it by Kingdom of Great Britain>British forces ended.	(File:United States Central change 1777-03-04.png	250px)

!scope=row|June 4, 1777

Vermont Republic>Vermont.	Disputes:(File:United States Central dispute change 1777-06-04.png|alt=Map of the change to the international disputes involving the United States in central North America on June 4, 1777|250px)

!scope=row|September 27, 1777|The Continental Congress fled Philadelphia after the American defeat at the Battle of Brandywine, and briefly met in Lancaster, Pennsylvania

(File:United States Central change 1777-09-27.png	250px)

!scope=row|September 30, 1777|The Continental Congress continued to move away from Philadelphia, settling in York, Pennsylvania.

(File:United States Central change 1777-09-30.png	250px)

!scope=row|June 11, 1778

Vermont Republic>Vermont claimed what was called the “East Union”, consisting of some towns in New Hampshire that petitioned on March 12, 1778, to join with Vermont, out of concern that their state was focusing too much on its coastal region. Vermont never gained full control over the area.Vermont State Papers, pp. 89–103{{efn	Littleton, New Hampshire>Apthorp (now Littleton), Bath, New Hampshire	, Canaan, New Hampshire>Canaan, Orange, New Hampshire	(now Orange), Cornish, New Hampshire>Cornish, Hanover, New Hampshire	(now part of Hanover), Enfield, New Hampshire>Enfield, Franconia, New Hampshire	, Lisbon, New Hampshire>Gunthwaite (now Lisbon), Haverhill, New Hampshire	, Landaff, New Hampshire>Landaff, Lebanon, New Hampshire	, Lyman, New Hampshire>Lyman, Lyme, New Hampshire	, Orford, New Hampshire>Orford, and Piermont. The specific extent of the towns annexed is unknown, as township borders were often delineated only when a dispute arose; the map uses the common interpretation.}}	Disputes:(File:United States Central dispute change 1778-06-11.png	250px)

!scope=row|October 21, 1778

Continental Congress, Vermont Republic>Vermont rescinded the annexation of the East Union; the legislature declared on February 12, 1779, that the East Union should be considered null from its beginning.	Disputes:(File:United States Central dispute change 1778-10-21.png	250px)

!scope=row|July 2, 1779

Continental Congress returned to Philadelphia following Kingdom of Great Britain>British withdrawal.	(File:United States Central change 1779-07-02.png	250px)

!scope=row|August 31, 1779

Virginia surrendered its District of West Augusta>claim to southwest Pennsylvania.CRUMRINE>FIRST=BOYD	TITLE=BOUNDARY CONTROVERSY BETWEEN PENNSYLVANIA AND VIRGINIA; 1748–1785	JOURNAL=ANNALS OF CARNEGIE MUSEUM	ISSUE=4	DOI=10.5962/P.331066	ACCESS-DATE=AUGUST 20, 2017, free,	(File:United States Central change 1779-08-31.png	250px)

!scope=row|March 1780

North Carolina and Virginia surveyed their border further inland. Virginia’s survey reached to the Tennessee River, but North Carolina’s only went as far as the Cumberland Gap, and as the two surveys were roughly two miles apart, this created a thin area claimed by both states. While the border was intended to follow parallel 36°30′ north>36°30′ north, early surveying errors caused it to veer north of that, reaching a distance of almost ten miles off by the time it reached the Tennessee River.HTTP://WWW.VIRGINIAPLACES.ORG/BOUNDARIES/TNBOUNDARY.HTML >TITLE=VIRGINIA-TENNESSEE BORDER	URL-STATUS=LIVE	ARCHIVE-DATE=AUGUST 1, 2023,	(File:United States Central change 1780-03-00.png	250px)

!scope=row|October 25, 1780

Constitution of Massachusetts>constitution, renaming itself the Commonwealth of Massachusetts.	(File:United States Central change 1780-10-25.png	250px)

!scope=row|March 1, 1781|The Articles of Confederation entered into force.WEB ,

no change to map

!scope=row|April 4, 1781

Vermont Republic>Vermont again claimed an East Union, consisting of some towns in New Hampshire that wished to join with Vermont; more towns were interested than during the first attempt in 1778, though again, the exact extent of the borders is unknown. Vermont never gained full control over the area.Vermont State Papers, pp. 136–137: “Agreeably to the recommendation of the committees, the Legislature of Vermont was adjourned to the first Wednesday of April [1781]; at which time, it met at Windsor, and the union of the grants, east and west of Connecticut river, was consummated“HTTP://ACADEMICS.SMCVT.EDU/VTGEOGRAPHIC/TEXTBOOK/HISTORICAL/HISTORICAL_GEOGRAPHY_OF_VERMONT.HTM >TITLE=THE HISTORICAL GEOGRAPHY OF VERMONT

ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160112223456/HTTP://ACADEMICS.SMCVT.EDU/VTGEOGRAPHIC/TEXTBOOK/HISTORICAL/HISTORICAL_GEOGRAPHY_OF_VERMONT.HTM

YEAR=2003

ID=1584650869

PAGE=111

The New Hampshire towns petitioning to join Vermont were: Acworth, New Hampshire

, Alstead, New Hampshire>Alstead, Bath, New Hampshire

, Orange, New Hampshire>Cardigan (now Orange), Charlestown, New Hampshire

, Chesterfield, New Hampshire>Chesterfield, Claremont, New Hampshire

, Cornish, New Hampshire>Cornish, Croydon, New Hampshire

, Dorchester, New Hampshire>Dorchester, Hanover, New Hampshire

, Franconia, New Hampshire>Franconia, “Gilsom” (likely Gilsum, New Hampshire

), Grafton, New Hampshire>Grafton, Grantham, New Hampshire

, Lisbon, New Hampshire>Gunthwaite (now Lisbon), Hanover, New Hampshire

, Haverhill, New Hampshire>Haverhill, Hinsdale, New Hampshire

, Landaff, New Hampshire>Landaff, Lancaster, New Hampshire

, Lebanon, New Hampshire>Lebanon, “Leinster” (possibly Lempster, New Hampshire

), Lincoln, New Hampshire>Lincoln, Lyman, New Hampshire

, Lyme, New Hampshire>Lyme, Marlow, New Hampshire

, Newport, New Hampshire>Newport, Piermont, New Hampshire

, Plainfield, New Hampshire>Plainfield, Richmond, New Hampshire

, Sunapee, New Hampshire>Saville (now Sunapee), Surry, New Hampshire

, Walpole, New Hampshire>Walpole, and Westmoreland. The specific extent of the towns annexed is unknown, as township borders were often delineated only when a dispute arose; the map uses the common interpretation.}}

Disputes:(File:United States Central dispute change 1781-04-04.png

250px)

!scope=row|June 16, 1781

Vermont Republic>Vermont claimed what was called the “West Union”, consisting of some towns in New York (state)

, mainly to counterbalance Vermont’s attempt at eastward expansion. Vermont never gained full control over the area.Vermont State Papers, pp. 138–141THE VERMONT ENCYCLOPEDIA

YEAR=2003

ID=1584650869

PAGE=319

The New York towns petitioning to join Vermont were: “Black-Creek” (unknown; possibly is or is near Hebron, New York

), Cambridge, New York>Cambridge, Fort Edward (town), New York

, Granville, New York>Granville, “Greenfield” (unknown; there is a town named Greenfield, New York

but it lies west of the Hudson River, which was explicitly the western extent of the West Union), Hoosick, New York>Hoosick, Kingsbury, New York

, “Little Hoosack” (unknown; presumably near Hoosick), Saratoga, New York>Saratoga, “Scorticook” (possibly Schaghticoke (town), New York

), Whitehall (village), New York>Skeensborough (now Whitehall), and “Upper-White-Creek” (probably White Creek). The specific extent of the towns annexed is unknown, as township borders were often delineated only when a dispute arose; the map uses the common interpretation.}}

Disputes:(File:United States Central dispute change 1781-06-16.png

250px)

!scope=row|February 22, 1782

Vermont Republic>Vermont abandoned its attempts to annex the East Union from New Hampshire and the West Union from New York (state)	.{{ussc>name=Vermont v. New Hampshire	page=593|year=1933}}	Disputes:(File:United States Central dispute change 1782-02-22.png	250px)

!scope=row|October 29, 1782

state cessions>cession from New York (state)	of its western claims, which the state ceded on February 19, 1780, and executed on March 1, 1781; New York proclaimed its new western border to be a line drawn south from the western end of Lake Ontario. At its maximum interpretation, the state had claimed an area bounded by Lake Erie, Lake Huron and Lake Michigan; to the Illinois River>Illinois, Mississippi River	, and Tennessee River>Tennessee Rivers; and north along the Appalachian Mountains, ending at the border with Pennsylvania.Walker, p.65 It is unclear from where this claim came; many sources state that New York had surrendered it, but very few elaborate on how it was obtained. One source states that it was a cession by the Iroquois	, who had conquered much of the region.HTTP://WWW.VIRGINIAPLACES.ORG/BOUNDARIES/CESSIONS.HTML	ACCESS-DATE=JUNE 21, 2016	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160817091436/HTTP://WWW.VIRGINIAPLACES.ORG/BOUNDARIES/CESSIONS.HTML	Erie Triangle.HTTPS://BOOKS.GOOGLE.COM/BOOKS?ID=YIWMAQAAMAAJ&PG=PA384	AUTHOR=SPENCER, JESSE AMES	YEAR=1912,	alt=Map of the change to the United States in central North America on October 29, 1782|250px)

!scope=row|December 30, 1782

Congress of the Confederation declared that the land that Connecticut claimed in northern Pennsylvania was part of Pennsylvania, thus attempting to end the Pennamite–Yankee War.PROCEEDINGS OF THE NEW JERSEY HISTORICAL SOCIETY	YEAR=1921	AUTHOR=GNICHTEL, FREDERICK W.	ACCESS-DATE=NOVEMBER 8, 2015, The claim was an extension of Connecticut’s northernmost and southernmost borders westward, skipping New Jersey and New York, though as Connecticut’s northern border was a few miles north of Pennsylvania’s northern border, a small sliver of New York was also claimed. While conflict would continue for some time, this was the end of the formal claim by Connecticut.	alt=Map of the change to the United States in central North America on December 30, 1782|250px)

!scope=row|June 30, 1783

Pennsylvania Mutiny of 1783, and the Pennsylvania government reaction to it, caused the Congress of the Confederation to leave Philadelphia for Princeton, New Jersey>Princeton.	(File:United States Central change 1783-06-30.png	250px)

!scope=row|November 26, 1783

Congress of the Confederation reconvened in Annapolis, Maryland>Annapolis.	(File:United States Central change 1783-11-26.png	250px)

!scope=row|March 1, 1784

Virginia ceded Illinois County, Virginia>its claims northwest of the Ohio River to the federal government.JOURNALS OF THE CONTINENTAL CONGRESS, 1774–1789>PAGES=VOL. 26, PP. 112–121	EDITOR=WORTHING C. FORD, etal, Connecticut continued to claim its western lands that had overlapped with Virginia’s cession.	alt=Map of the change to the United States in central North America on March 1, 1784|250px)

!scope=row|May 12, 1784

Kingdom of Great Britain>Great Britain Treaty of Paris (1783)	the independence of the United States, ending its claim to the country.Van Zandt, pp.10–22Treaty of Paris, 1783; International Treaties and Related Records, 1778–1974; General Records of the United States Government, Record Group 11; National Archives.{{efn>The treaty established the boundaries of the new country, from the Bay of Fundy: up the “St. Croix River” (which river this referred to was disputed) to its source; north to the height of the land (the “Northwest Angle of Nova Scotia“); along the height of the land to the “northwesternmost Head” of the Connecticut River (which source this referred to was disputed); down that to 45th parallel north	; west to the St. Lawrence River; up that to the Great Lakes, through Lake Ontario, the Niagara River, Lake Erie, the Detroit River, Lake St. Clair, the St. Clair River, Lake Huron, and Lake Superior; to “Long Lake” (which lake this referred to was disputed) towards the Lake of the Woods; to the northwest angle of the Lake of the Woods; then west to the Mississippi River. However, the Lake of the Woods was north of the source of the Mississippi River; maps universally show this undefined border as a straight line, nearly straight south, between the two points. From there, it followed the Mississippi River down to 31st parallel north>31° north; east to the Chattahoochee River; down that to the confluence of the Chattahoochee and Flint River (Georgia)	rivers; a line from there to the source of the St. Marys River (Florida–Georgia)>St. Mary’s River; then down that to the Atlantic Ocean.}} The treaty ended the American Revolutionary War, though military action had largely ended after the Franco-American alliance	victory at Siege of Yorktown>Yorktown on October 19, 1781.Because of ambiguities and poor knowledge of geography, the treaty was unclear in several areas: The northeastern border was defined as running from the headlands of the St. Croix River, but there were several options for that. The northwestern border was defined as a line running west from the northwestern point of the Lake of the Woods to the Mississippi River, but the river’s source was south of that; maps universally show the line as running directly from the Lake of the Woods to the river’s source, Lake Itasca. The border extending from Lake Superior towards the Lake of the Woods was poorly defined as starting from “Long Lake”, which both sides interpreted to their advantage. Machias Seal Island and North Rock off the northeast coast remained disputed, as did Sugar Island off the Upper Peninsula of Michigan. The Peace of Paris also involved treaties with France and Spain, with Great Britain ceding the Floridas to Spain. During their ownership of West Florida, the British had moved its border north, and the cession to Spain appeared to apply to the full extent of the British colony. However, the British-American treaty granted the extension of West Florida to the United States, where it enlarged Georgia south to 31° north, indicating that only the original definition of West Florida was to be ceded to Spain. The local Spanish governors also made a move to occupy forts along the Mississippi River, with claims to everything south of the Tennessee River; it is unknown how official or strong these claims were, and they are not mapped as they are in conflict with the other Spanish claim involving the border of West Florida.BOOK,archive.org/details/historyoftenness00mcgerich, A History of Tennessee from 1663 to 1914: For Use in Schools, American Book Company, McGee, Gentry Richard, 95–99, December 29, 2015, 1911,	(File:United States Central change 1784-05-12.png	250px)Disputes:(File:United States Central dispute change 1784-05-12.png	250px)

“>

1784–1803 (Organization of territory){|class“wikitable plainrowheaders”

!scope=“col“|Date!scope=“col“|Event!scope=“col“|Change Map!scope=row|August 23, 1784

North Carolina (modern-day eastern Tennessee), unhappy with the state’s governance over the area, declared independence from the state as the State of Franklin>State of Frankland.{{efn		YEAR=1933	PAGE=30, The government of Frankland held some control over the area, and petitioned for statehood, receiving support from seven of the nine states required, but would only last a few years.HTTP://WWW.BND.COM/LIVING/LIV-COLUMNS-BLOGS/ANSWER-MAN/ARTICLE100650397.HTML >TITLE=THE STATE THAT ALMOST WAS AN ORIGINAL COLONY	ACCESS-DATE=MARCH 13, 2017	AUTHOR=SCHLUETER, ROGER	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160909150837/HTTP://WWW.BND.COM/LIVING/LIV-COLUMNS-BLOGS/ANSWER-MAN/ARTICLE100650397.HTML, September 9, 2016,	Unofficial change:(File:United States Central change 1784-08-23.png	250px)

!scope=row|November 1, 1784

Congress of the Confederation moved for a short time to Trenton, New Jersey>Trenton.	(File:United States Central change 1784-11-01.png	250px)

!scope=row|January 11, 1785

Congress of the Confederation moved to New York City>New York, and would settle there for five years.	(File:United States Central change 1785-01-11.png	250px)

!scope=row|April 19, 1785

state cessions>cession from Massachusetts of its extreme western claim, which was never seriously enforced.{{efn	New York (state)>New York and Pennsylvania stretching to the Mississippi River, bounded by the latitudes of Massachusetts Bay Colony’s original charter: on the north by a line west from one league north of Lake Winnipesaukee, and on the south by a line west from Massachusetts’ southwest corner.}}	Change on paper only:(File:United States Central change 1785-04-19.png	250px)

!scope=row|June 1785|The State of Frankland was renamed the State of Franklin, to encourage Benjamin Franklin to endorse the state, though he declined.

Unofficial change:(File:United States Central change 1785-06-00.png	250px)

!scope=row|September 13, 1786

Connecticut surrendered its western claim to the federal government except for its Connecticut Western Reserve>Western Reserve, though it is unclear how much control they held over the ceded region.{{efn	Pennsylvania (the western border of its Connecticut Western Reserve>Western Reserve) stretching to the Mississippi River, bounded by 41° north and the southern edge of Massachusetts’s western claim, roughly 42°2′ north.}}Van Zandt, pp. 47–49	Change on paper only:(File:United States Central change 1786-09-13.png	250px)

!scope=row|December 16, 1786

Massachusetts Treaty of Hartford (1786)>surrendered its claim to western New York (state)	, though it is unclear if Massachusetts ever held control over the region, as the claim was to the “soil, not the sovereignty”.{{efn>Massachusetts’s ceded claim was the portion of New York 82 miles west of where the Delaware River left New York, to an unclear western boundary, with one source saying it was as far as one mile east of the Niagara River.}} This land was later known as the Phelps and Gorham Purchase.	Change on paper only:(File:United States Central change 1786-12-16.png	250px)

!scope=row|July 13, 1787

Ohio River>River Ohio, ceded earlier by Virginia, was organized and commonly became known as the Northwest Territory.Van Zandt, pp. 111–114Northwest Ordinance, July 13, 1787; (National Archives Microfilm Publication M332, roll 9); Miscellaneous Papers of the Continental Congress, 1774–1789; Records of the Continental and Confederation Congresses and the Constitutional Convention, 1774–1789, Record Group 360; National Archives.

alt=Map of the change to the United States in central North America on July 13, 1787|250px)

!scope=row|August 9, 1787

South Carolina ceded its western claim to the federal government,JOURNALS OF THE CONTINENTAL CONGRESS, 1774–1789	PAGES=466–477	EDITOR=WORTHINGTON C. FORD	North Carolina and the source of the Tugaloo River but, unknown at the time, the river originated in North Carolina. The eastern part of this cession would be given to Georgia (U.S. state)>Georgia in 1802, despite Georgia technically already having claim to the land.COTTERILL >FIRST=R. S.	TITLE=THE SOUTH CAROLINA LAND CESSION	JOURNAL=THE MISSISSIPPI VALLEY HISTORICAL REVIEW	ISSUE=3	DOI=10.2307/1889567, 0161-391X,	Change on paper only:(File:United States Central change 1787-08-09.png	250px)

!scope=row|December 7, 1787|Delaware became the first state to ratify the United States Constitution.WEB ,

no change to map

!scope=row|December 12, 1787

Pennsylvania became the second state to ratify the United States Constitution>Constitution.WEB ,avalon.law.yale.edu/18th_century/ratpa.asp , Ratification of the Constitution by the State of Pennsylvania; December 12, 1787 , The Avalon Project at Yale Law School , October 31, 2015 , live ,avalon.law.yale.edu/18th_century/ratpa.asp" title="web.archive.org/web/20151105061228avalon.law.yale.edu/18th_century/ratpa.asp">web.archive.org/web/20151105061228avalon.law.yale.edu/18th_century/ratpa.asp , November 5, 2015 ,

no change to map

!scope=row|December 18, 1787

New Jersey became the third state to ratify the United States Constitution>Constitution.WEB ,avalon.law.yale.edu/18th_century/ratnj.asp , Ratification of the Constitution by the State of New Jersey; December 18, 1787 , The Avalon Project at Yale Law School , October 31, 2015 , live ,avalon.law.yale.edu/18th_century/ratnj.asp" title="web.archive.org/web/20150923083203avalon.law.yale.edu/18th_century/ratnj.asp">web.archive.org/web/20150923083203avalon.law.yale.edu/18th_century/ratnj.asp , September 23, 2015 ,

no change to map

!scope=row|January 2, 1788

Georgia (U.S. state)>Georgia became the fourth state to ratify the Constitution.WEB ,avalon.law.yale.edu/18th_century/ratga.asp , Ratification of the Constitution by the State of Georgia; January 2, 1788 , The Avalon Project at Yale Law School , October 31, 2015 , live ,avalon.law.yale.edu/18th_century/ratga.asp" title="web.archive.org/web/20151220224732avalon.law.yale.edu/18th_century/ratga.asp">web.archive.org/web/20151220224732avalon.law.yale.edu/18th_century/ratga.asp , December 20, 2015 ,

no change to map

!scope=row|January 6, 1788

Connecticut became the fifth state to ratify the United States Constitution>Constitution.WEB ,avalon.law.yale.edu/18th_century/ratct.asp , Ratification of the Constitution by the State of Connecticut; January 8, 1788 , The Avalon Project at Yale Law School , October 31, 2015 , live ,avalon.law.yale.edu/18th_century/ratct.asp" title="web.archive.org/web/20151107080241avalon.law.yale.edu/18th_century/ratct.asp">web.archive.org/web/20151107080241avalon.law.yale.edu/18th_century/ratct.asp , November 7, 2015 ,

no change to map

!scope=row|February 6, 1788

Massachusetts became the sixth state to ratify the United States Constitution>Constitution.WEB ,avalon.law.yale.edu/18th_century/ratma.asp , Ratification of the Constitution by the State of Massachusetts; February 6, 1788 , The Avalon Project at Yale Law School , October 31, 2015 , live ,avalon.law.yale.edu/18th_century/ratma.asp" title="web.archive.org/web/20160209044703avalon.law.yale.edu/18th_century/ratma.asp">web.archive.org/web/20160209044703avalon.law.yale.edu/18th_century/ratma.asp , February 9, 2016 ,

no change to map

!scope=row|April 28, 1788

Maryland became the seventh state to ratify the United States Constitution>Constitution.WEB ,avalon.law.yale.edu/18th_century/ratme.asp , Ratification of the Constitution by the State of Maryland; April 28, 1788 , The Avalon Project at Yale Law School , October 31, 2015 , live ,avalon.law.yale.edu/18th_century/ratme.asp" title="web.archive.org/web/20150710125028avalon.law.yale.edu/18th_century/ratme.asp">web.archive.org/web/20150710125028avalon.law.yale.edu/18th_century/ratme.asp , July 10, 2015 ,

no change to map

!scope=row|May 23, 1788

South Carolina became the eighth state to ratify the United States Constitution>Constitution.WEB ,avalon.law.yale.edu/18th_century/ratsc.asp , Ratification of the Constitution by the State of South Carolina; May 23, 1788 , The Avalon Project at Yale Law School , October 31, 2015 , live ,avalon.law.yale.edu/18th_century/ratsc.asp" title="web.archive.org/web/20151108102025avalon.law.yale.edu/18th_century/ratsc.asp">web.archive.org/web/20151108102025avalon.law.yale.edu/18th_century/ratsc.asp , November 8, 2015 ,

no change to map

!scope=row|June 21, 1788

New Hampshire became the ninth state to ratify the United States Constitution>Constitution;WEB ,avalon.law.yale.edu/18th_century/ratnh.asp , Ratification of the Constitution by the State of New Hampshire; June 21, 1788 , The Avalon Project at Yale Law School , October 31, 2015 , live ,avalon.law.yale.edu/18th_century/ratnh.asp" title="web.archive.org/web/20151105061223avalon.law.yale.edu/18th_century/ratnh.asp">web.archive.org/web/20151105061223avalon.law.yale.edu/18th_century/ratnh.asp , November 5, 2015 , at this point, the Constitution became the active governing document of those nine states having ratified the same (per Article VII).

no change to map

!scope=row|June 25, 1788

Virginia became the tenth state to ratify the United States Constitution>Constitution.WEB ,avalon.law.yale.edu/18th_century/ratva.asp , Ratification of the Constitution by the State of Virginia; June 26, 1788 , The Avalon Project at Yale Law School , October 31, 2015 , live ,avalon.law.yale.edu/18th_century/ratva.asp" title="web.archive.org/web/20150822161000avalon.law.yale.edu/18th_century/ratva.asp">web.archive.org/web/20150822161000avalon.law.yale.edu/18th_century/ratva.asp , August 22, 2015 ,

no change to map

!scope=row|July 26, 1788

New York (state)>New York became the eleventh state to ratify the Constitution.WEB ,avalon.law.yale.edu/18th_century/ratny.asp , Ratification of the Constitution by the State of New York; July 26, 1788 , The Avalon Project at Yale Law School , October 31, 2015 , live ,avalon.law.yale.edu/18th_century/ratny.asp" title="web.archive.org/web/20151024010823avalon.law.yale.edu/18th_century/ratny.asp">web.archive.org/web/20151024010823avalon.law.yale.edu/18th_century/ratny.asp , October 24, 2015 ,

no change to map

!scope=row|February 1789

John Sevier, governor of the State of Franklin, pledged allegiance to North Carolina, effectively ending the claimed independence of Franklin.HISTORY OF THE LOST STATE OF FRANKLIN	YEAR=1933	PAGE=230,	Unofficial change:(File:United States Central change 1789-02-00.png	250px)

!scope=row|August 7, 1789

Northwest Territory was reorganized under the United States Constitution>Constitution.{{usstat	50}}	no change to map

!scope=row|November 21, 1789

North Carolina became the twelfth state to ratify the United States Constitution>Constitution.WEB ,avalon.law.yale.edu/18th_century/ratnc.asp , Ratification of the Constitution by the State of North Carolina; November 21, 1789 , The Avalon Project at Yale Law School , October 31, 2015 , live ,avalon.law.yale.edu/18th_century/ratnc.asp" title="web.archive.org/web/20151123223225avalon.law.yale.edu/18th_century/ratnc.asp">web.archive.org/web/20151123223225avalon.law.yale.edu/18th_century/ratnc.asp , November 23, 2015 ,

no change to map

!scope=row|April 2, 1790

North Carolina ceded its western half to the federal government.{{efn>The new North Carolina–federal border was, from the north, southwest along various ridges of the Great Smoky Mountains; however, issues caused surveyors to eventually run a line roughly due south rather than continue along the ridge.}}{{usstat	106}}	alt=Map of the change to the United States in central North America on April 2, 1790|250px)

!scope=row|May 26, 1790

North Carolina was organized as the Territory South of the River Ohio, commonly known as the Southwest Territory.Van Zandt, pp. 109–111{{usstat>1|123}}	alt=Map of the change to the United States in central North America on May 26, 1790|250px)

!scope=row|May 29, 1790

Rhode Island became the thirteenth state to ratify the United States Constitution>Constitution.WEB ,avalon.law.yale.edu/18th_century/ratri.asp , Ratification of the Constitution by the State of Rhode Island; May 29, 1790 , The Avalon Project at Yale Law School , October 30, 2015 , live ,avalon.law.yale.edu/18th_century/ratri.asp" title="web.archive.org/web/20151122110326avalon.law.yale.edu/18th_century/ratri.asp">web.archive.org/web/20151122110326avalon.law.yale.edu/18th_century/ratri.asp , November 22, 2015 ,

no change to map

!scope=row|December 6, 1790

Residence Act, the United States Congress>Congress of the United States relocated to Philadelphia for ten years until a Washington, D.C.	was built and ready.{{usstat>1|130}}	(File:United States Central change 1790-12-06.png	250px)

!scope=row|March 4, 1791

Vermont, which had been considered part of New York (state)>New York despite Vermont Republic	since 1777, was admitted as the fourteenth state.{{efn>The new New York–Vermont border was, from the north: Lake Champlain, the Poultney River, then south following borders of townships.}}Van Zandt, pp. 64–65{{usstat	191}}	(File:United States Central change 1791-03-04.png	250px)Disputes:(File:United States Central dispute change 1791-03-04.png	250px)

!scope=row|March 30, 1791

District of Columbia, a federal district planned to house the federal government by 1800, was Residence Act>formed from land ceded by Maryland and Virginia,{{usstat	130}}, {{usstat	214}} consisting of a 100 square mile diamond, with its southern tip at Jones Point (Virginia)	, straddling the Potomac River. However, it was not yet given that name, being simply referred to as the federal district. In September 1791, the commissioners in charge of planning the city would term it the “Territory of Columbia”, and various laws refer to a District of Columbia, but sometimes informally. The area does not appear to have been formally named “District of Columbia” until at least the District of Columbia Organic Act of 1871>organic act of 1871.JOURNAL, Tindall, William, February 25, 1919, Naming the Seat of Government of the United States: A Legislative Paradox, Records of the Columbia Historical Society, Historical Society of Washington, D.C., 23, 40067136, 10–25, Since the name “Columbia” was used from very early on, and at least informally by the government, the map will use “District of Columbia” starting from this date.	alt=Map of the change to the United States in central North America on March 30, 1791|250px)

!scope=row|March 3, 1792|Pennsylvania purchased the Erie Triangle from the federal government.

alt=Map of the change to the United States in central North America on March 3, 1792|250px)

!scope=row|June 1, 1792

Virginia, which the state had agreed in 1789 to cede to the federal government,Virginia Compacts, § 1-307. Compact and boundary with Kentucky {{webarchive>url=https://web.archive.org/web/20160624063836law.lis.virginia.gov/compacts/compact-and-boundary-with-kentucky/	Kentucky.{{efn>The new Kentucky–Virginia border was, from the south: north along the Cumberland Mountains and Pine Mountain (Appalachian Mountains)	to the Russell Fork; northeast to the Tug Fork; then down that to the Big Sandy River (Ohio River tributary)>Big Sandy River and to the Ohio River.}}{{usstat	189}}Van Zandt, p. 111	alt=Map of the change to the United States in central North America on June 1, 1792|250px)

!scope=row|June 12, 1792

Delaware Constitution of 1792>new constitution, renaming itself the Delaware	.THE FEDERAL AND STATE CONSTITUTIONS, COLONIAL CHARTERS, AND OTHER ORGANIC LAWS OF THE STATES, TERRITORIES, AND COLONIES NOW OR HERETOFORE FORMING THE UNITED STATES OF AMERICA	PUBLISHER=UNITED STATES GOVERNMENT PUBLISHING OFFICE	> AUTHOR = THORPE, FRANCIS NEWTON	PAGE=568	ISBN=0-89941-792-2,	no change to map

!scope=row|August 3, 1795

Western Confederacy sign the Treaty of Greenville, ending the Northwest Indian War and ceding most of the modern state of Ohio to United States control.HEMENWAY ERIC	TITLE=SUMMER 1795: THE TREATY OF GREENVILLE CREATES AN UNEASY PEACE	NATIONAL PARK SERVICE >URL=HTTPS://WWW.NPS.GOV/ARTICLES/A-LONG-LEGACY.HTM, 21 April 2020,	no change to map

!scope=row|February 29, 1796

Kingdom of Great Britain>Great Britain Jay Treaty	to abandon several forts in the northwest that it still occupied, including Detroit. The Jay Treaty also provided for commissions to determine the border between the northwestern point of the Lake of the Woods and the Lake Itaska>source of the Mississippi River, and which river to consider the St. Croix River (Maine–New Brunswick)	.HTTPS://WWW.LOC.GOV/RR/PROGRAM/BIB/OURDOCS/JAY.HTML	PUBLISHER=LIBRARY OF CONGRESS	URL-STATUS=LIVE	ARCHIVE-DATE=OCTOBER 27, 2015,	no change to map

!scope=row|April 25, 1796

West Florida was Pinckney’s Treaty>ceded by Spain, resolving the dispute over the region.WEB ,avalon.law.yale.edu/18th_century/sp1795.asp , Treaty of Friendship, Limits, and Navigation Between Spain and The United States; October 27, 1795 , The Avalon Project at Yale Law School , October 30, 2015 , live ,avalon.law.yale.edu/18th_century/sp1795.asp" title="web.archive.org/web/20151112201043avalon.law.yale.edu/18th_century/sp1795.asp">web.archive.org/web/20151112201043avalon.law.yale.edu/18th_century/sp1795.asp , November 12, 2015 , Van Zandt, p. 22	Disputes:(File:United States Central dispute change 1796-04-25.png	250px)

!scope=row|June 1, 1796

Southwest Territory was admitted as the sixteenth state, Tennessee.{{usstat>1|491}}	alt=Map of the change to the United States in central North America on June 1, 1796|250px)

!scope=row|April 7, 1798

Yazoo Land Fraud, an act authorized President John Adams to appoint commissioners to negotiate with Georgia (U.S. state)>Georgia about ceding its western land. The act created Mississippi Territory from the southwestern quarter of Georgia in the region recently ceded by West Florida, while maintaining that Georgia still held rights over the territory.{{usstat	549}}Van Zandt, pp. 105–106	alt=Map of the change to the United States in central North America on April 7, 1798|250px)

!scope=row|October 25, 1798

St. Croix River (Maine–New Brunswick)>St. Croix River, setting the lower portion of the border between Massachusetts and Great Britain and, thus, where the eastern north–south line originated.Van Zandt, p. 12	(File:United States Central change 1798-10-25.png	250px)Disputes:(File:United States Central dispute change 1798-10-25.png	250px)

!scope=row|June 9, 1800

Connecticut ceded its Connecticut Western Reserve>Western Reserve to the federal government, which assigned it to the Northwest Territory.{{usstat	56}} The act doing so was passed in Congress on April 28, 1800, and Connecticut approved it on this date.HTTPS://BOOKS.GOOGLE.COM/BOOKS?ID=CYYUAAAAYAAJ&PG=PA216 >ACCESS-DATE=OCTOBER 29, 2015	URL-STATUS=LIVE	ARCHIVE-DATE=JUNE 4, 2016, 1916,	alt=Map of the change to the United States in central North America on June 9, 1800|250px)

!scope=row|July 4, 1800

Indiana Territory was organized from the western half of Northwest Territory.{{efn>The new Indiana Territory–Northwest Territory border was, from the south, a line from the mouth of the Kentucky River to Fort Recovery, then north.}}{{usstat	58}}Van Zandt, pp. 114–115	alt=Map of the change to the United States in central North America on July 4, 1800|250px)

!scope=row|November 17, 1800

United States Congress>Congress of the United States moved to Washington, D.C.	in the District of Columbia, now built and ready to be the capital. This was two weeks before the December 1 date established in the Residence Act; President John Adams urged Congress to move early in hopes of securing enough Southern votes to be re-elected, though this failed.{{citation >author=Carter II, Edward C.	journal=Records of the Columbia Historical Society	pages=139}}	(File:United States Central change 1800-11-17.png	250px)

!scope=row|January 1, 1801

Kingdom of Great Britain Acts of Union 1800>united with the Kingdom of Ireland, renaming itself the United Kingdom of Great Britain and Ireland	.HTTP://WWW.RAHBARNES.DEMON.CO.UK/UNION/UNION1800.HTM	ACCESS-DATE=NOVEMBER 10, 2015	ARCHIVE-DATE=SEPTEMBER 23, 2015,	alt=Map of the change to international disputes involving the United States in central North America on January 1, 1801|250px)

!scope=row|February 27, 1801

District of Columbia was District of Columbia Organic Act of 1801>organized.{{usstat	103}}	no change to map

!scope=row|April 26, 1802

Georgia (U.S. state)>Georgia ceded its western half, known as the Yazoo Lands, to the federal government.{{efn	Chattahoochee River to its great bend (near West Point, Georgia>West Point), then a line from there towards and past Nickajack. The border’s description said it would go until it reached the Tennessee River, and follow that up the river to Tennessee, but the river lay entirely within Tennessee.}} At the same time, the federal government ceded to Georgia the eastern portion of the land previously ceded by South Carolina, though in reality Georgia technically already held title to the land, as the description of the earlier cession was based on an erroneous understanding of geography.	alt=Map of the change to the United States in central North America on April 26, 1802|250px)

!scope=row|March 1, 1803

Northwest Territory, along with a thin sliver of Indiana Territory, was admitted as the seventeenth state, Ohio. The remainder of the Northwest Territory was transferred to Indiana Territory.{{usstat>2	Great Miami River; the federal definition of the northern border was a line drawn east from the southern tip of Lake Michigan, whereas the Ohio Constitution stated the line should run from the southern tip of Lake Michigan to the most northerly cape of Maumee Bay, essentially the western tip of Lake Erie. The confusion caused by these varying descriptions of the state’s borders, combined with inaccurate knowledge of geography, as no one at the time knew just how far south Lake Michigan extended, would lead to the Toledo War>conflict over the Toledo Strip.	alt=Map of the change to the United States in central North America on March 1, 1803|250px)

!scope=row|November 3, 1803

Tennessee and Virginia was resurveyed and established, ending the dispute over that part of the border. The border between Kentucky and Tennessee, despite following the original survey, remained vaguely defined.{{ussc>name=Virginia v. Tennessee	page=503|year=1893}}	alt=Map of the change to the United States in central North America on November 3, 1803|250px)

!scope=row|November 30, 1803

Southwick Jog” was transferred from Connecticut to Massachusetts, to put to rest long-standing disagreements over the border between the two states. The final report of the commissioners was delivered this day;HTTPS://CDM15019.CONTENTDM.OCLC.ORG/DIGITAL/COLLECTION/P128501COLL3/ID/37257	PAGES=1540–1544	LANGUAGE=EN, it is unclear when the change formally occurred.	alt=Map of the change to the United States in central North America on November 30, 1803|250px)

“>

1803–1818 (Purchase of Louisiana){|class“wikitable plainrowheaders”

!scope=“col“|Date!scope=“col“|Event!scope=“col“|Change Map!scope=row|December 20, 1803

Louisiana Purchase>purchased Louisiana from France. This is the date of the formal turnover in New Orleans; the purchase was completed on April 30, 1803. The transfer would be recognized in St. Louis in Upper Louisiana on March 10, 1804, known as Three Flags Day.The acquisition expanded the United States to the whole of the Mississippi River basin,{{efn|There was some question as to whether the purchase also included the basins of the Missouri River and the Red River of the North, but the question was not relevant before the Treaty of 1818 definitively settled the border. Maps universally show the purchase including the Missouri River basin but excluding the Red River basin.}} but the extent of what constituted Louisiana in the south was disputed with Spain: the United States claimed the purchase included the part of West Florida west of the Perdido River, whereas Spain claimed it ended at the western border of West Florida;{{efn|The western border of West Florida was a series of waterways, mainly the Mississippi, Iberville, and Amite Rivers, and Lakes Pontchartrain and Maurepas.}} and the southwestern border with New Spain was disputed, as the United States claimed the Sabine River as the border, but Spain maintained it was the Calcasieu River and others.	(File:United States Central change 1803-12-20.png	250px)Disputes:(File:United States Central dispute change 1803-12-20.png|alt=Map of the change to the international disputes involving the United States in central North America on December 20, 1803|250px)

!scope=row|March 27, 1804

Tennessee and Mississippi Territory previously ceded by Georgia (U.S. state)>Georgia was assigned to Mississippi Territory.{{usstat	303}}	alt=Map of the change to the United States in central North America on March 27, 1804|250px)

!scope=row|October 1, 1804

Orleans Territory was organized from the Louisiana Purchase south of 33rd parallel north>33° north, with the remainder being designated the District of Louisiana and placed under the jurisdiction of Indiana Territory.{{usstat	283}}Van Zandt, pp. 106–108	alt=Map of the change to the United States in central North America on October 1, 1804|250px)

!scope=row|June 30, 1805

Michigan Territory was organized from Indiana Territory, north of a line east from the southern tip of Lake Michigan, and east of a line north from the lake’s northern tip.{{usstat>2|309}}Van Zandt, pp. 127–128 The southeastern portion of the border technically conflicted with the definition of Ohio, which claimed the Toledo Strip north of that line; however, the exact position of Lake Michigan was not yet known.

alt=Map of the change to the United States in central North America on June 30, 1805|250px)

!scope=row|July 4, 1805

District of Louisiana was organized as Louisiana Territory.{{usstat>2|331}}	alt=Map of the change to the United States in central North America on July 4, 1805|250px)

!scope=row|March 1, 1809

Illinois Territory was organized from the western half of Indiana Territory.{{efn>The new Illinois Territory–Indiana Territory border was, from the south, the Wabash River up to Vincennes, Indiana	, then north.}}{{usstat>2|514}}Van Zandt, pp. 116–117	alt=Map of the change to the United States in central North America on March 1, 1809|250px)

!scope=row|September 26, 1810

Republic of West Florida declared independence from Spain, claiming the area of West Florida west of the Perdido River. It maintained some control over its territory.HTTP://WWW.INDEPENDENT.ORG/PUBLICATIONS/WORKING_PAPERS/ARTICLE.ASP?ID=1478	PUBLISHER=INDEPENDENT INSTITUTE	ACCESS-DATE=JUNE 14, 2016	ARCHIVE-DATE=MAY 23, 2016,	Disputes:(File:United States Central dispute change 1810-09-26.png	250px)

!scope=row|December 10, 1810

William C. C. Claiborne took possession of the portion of West Florida west of the Pearl River (Mississippi–Louisiana)>Pearl River, following a proclamation on October 27, 1810, by President James Madison to do so. The United States had considered the region part of the Louisiana Purchase, including the area which had revolted against Spanish Florida and formed the Republic of West Florida. Madison’s proclamation stated that it was to be “taken as part” of Orleans Territory.Van Zandt, pp. 23–26HTTP://MILLERCENTER.ORG/PRESIDENT/MADISON/SPEECHES/SPEECH-3610 >TITLE=PROCLAMATION—OCCUPATION OF WEST FLORIDA (OCTOBER 27, 1810)	MILLER CENTER OF PUBLIC AFFAIRS >ACCESS-DATE=OCTOBER 29, 2015	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20151030015016/HTTP://MILLERCENTER.ORG/PRESIDENT/MADISON/SPEECHES/SPEECH-3610	de facto by the military in 1811.THE WEST FLORIDA CONTROVERSY, 1798–1813 – A STUDY IN AMERICAN DIPLOMACY	PUBLISHER=THE JOHNS HOPKINS PRESS	DATE=1918	AUTHOR-LINK=ISAAC JOSLIN COX, {{rp|2a}}(map)	Disputes:(File:United States Central dispute change 1810-12-10.png	250px)

!scope=row|April 30, 1812

Orleans Territory was admitted as the eighteenth state, Louisiana.{{efn>The northwestern remainder of Orleans Territory presumably rejoined Louisiana Territory, as its extent was still vaguely defined.}}{{usstat	701}} The southeastern remainder presumably became unorganized territory, as it had no definition for a short time.	alt=Map of the change to the United States in central North America on April 30, 1812|250px)

!scope=row|May 14, 1812

West Florida east of the Pearl River (Mississippi–Louisiana)>Pearl River was assigned to Mississippi Territory, though the area around Mobile Bay remained under the control of Spanish Florida.{{usstat	734}} The United States militarily occupied Mobile and the surrounding area up to the Perdido River in April 1813.	alt=Map of the change to the United States in central North America on May 14, 1812|250px)

!scope=row|June 4, 1812

Louisiana, Louisiana Territory was renamed Missouri Territory.{{usstat>2|743}}Van Zandt, pp. 117–118	alt=Map of the change to the United States in central North America on June 4, 1812|250px)

!scope=row|August 4, 1812

West Florida, west of the Pearl River (Mississippi–Louisiana)>Pearl River, was added to Louisiana, following the assent of that state to an act passed by Congress on April 14, 1812.{{usstat	708}}A GENERAL DIGEST OF THE ACTS OF THE LEGISLATURE OF LOUISIANA: PASSED FROM THE YEAR 1804, TO 1827, INCLUSIVE > PAGE=9	ACCESS-DATE=OCTOBER 28, 2015	LAST2=LISLET	YEAR=1828,	alt=Map of the change to the United States in central North America on August 4, 1812|250px)

!scope=row|August 16, 1812

War of 1812, the garrison at Fort Shelby (Michigan)>Fort Detroit Siege of Detroit	, leading the United Kingdom of Great Britain and Ireland>United Kingdom to occupy Detroit, the capital and population center of Michigan Territory.HTTP://WWW.HISTORY.COM/THIS-DAY-IN-HISTORY/DETROIT-SURRENDERS-WITHOUT-A-FIGHT >TITLE=DETROIT SURRENDERS WITHOUT A FIGHT	ACCESS-DATE=JUNE 13, 2016	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160519093110/HTTP://WWW.HISTORY.COM/THIS-DAY-IN-HISTORY/DETROIT-SURRENDERS-WITHOUT-A-FIGHT, May 19, 2016,	Disputes:(File:United States Central dispute change 1812-08-16.png	250px)

!scope=row|September 29, 1813

Fort Shelby (Michigan)>Fort Detroit following the Battle of Lake Erie, allowing American forces to regain control over Michigan Territory.{{Citation | last = Farmer | first = Silas | year = 1884 | title = The History of Detroit and Michigan: Or, the Metropolis Illustrated | publisher = S. Farmer | location = Detroit | url =books.google.com/books?id=RH9FDeAyUJ4C | oclc = 359750 | page=224 }}	Disputes:(File:United States Central dispute change 1813-09-29.png	250px)

!scope=row|August 24, 1814

United Kingdom of Great Britain and Ireland>British forces Burning of Washington	, but are forced to withdraw the next day. The functions of the capital were only momentarily suspended, though President James Madison took refuge in Brookville, Maryland.HTTP://TOWNOFBROOKEVILLEMD.ORG/ABOUT/TOWN-HISTORY/	PUBLISHER=TOWN OF BROOKVILLE, MARYLAND	URL-STATUS=DEAD	ARCHIVE-DATE=MAY 5, 2016,	no change to map

!scope=row|December 11, 1816

Indiana Territory, along with small parts of Illinois Territory and Michigan Territory, were admitted as the nineteenth state, Indiana.{{efn>Indiana was defined as the territory north of the Ohio River and east of the Wabash River, but while the territory’s line turned north at Vincennes, Indiana	, the state’s border continued up the Wabash until it reached the point where a line drawn north from Post Vincennes would last intersect the river as it weaved back and forth. The northern border of the state was a line east from 10 miles north of the southern tip of Lake Michigan, until it reached the meridian that formed Ohio’s western border, which was a line drawn north from the mouth of the Great Miami River.}} The remainder of Indiana Territory across Lake Michigan became unorganized territory.{{usstat>3	3|399}}	alt=Map of the change to the United States in central North America on December 11, 1816|250px)

!scope=row|March 3, 1817

Alabama Territory was organized from the eastern half of Mississippi Territory.{{efn>The new Alabama Territory–Mississippi Territory border was, from the north: up the Tennessee River to Bear Creek (around today’s Pickwick Lake); a line to the northwestern corner of Washington County, Alabama	; then south.}}{{usstat>3|371}}Van Zandt, pp. 108–109	alt=Map of the change to the United States in central North America on March 3, 1817|250px)

!scope=row|December 10, 1817

Mississippi Territory was admitted as the twentieth state, Mississippi.{{usstat>3	3|472}}	alt=Map of the change to the United States in central North America on December 10, 1817|250px)

!scope=row|February 6, 1818

Alabama Territory created Tuscaloosa County, Alabama>Tuskaloosa County with a description that inadvertently overlapped with Mississippi. It described the border of the county as running “a due west course to, the Tombeckbe river; thence up the same to the Cotton Gin Port”.Alabama Terr. Acts 1818, 1st session, pp. 17–18 {{webarchive	www.legislature.state.al.us/aliswww/history/acts_and_journals/Acts_1818_Jan-Feb/Page3_pgs_11-20.html >date=March 4, 2016 }} Unknown at the time, the origin of the Tombigbee River and Cotton Gin Port were in Mississippi.	Change on paper only:(File:United States Central change 1818-02-06.png	250px)

!scope=row|June 30, 1818

Treaty of Ghent ending the War of 1812, the United Kingdom of Great Britain and Ireland>United Kingdom returned Moose Island, Maine	to Massachusetts, and the United States returned Campobello Island, Deer Island (New Brunswick)>Deer Island, and Grand Manan Island to the United Kingdom, all of which were captured from the other side during the war.HTTPS://ARCHIVE.ORG/DETAILS/MAINEINNORTHEAS00BURRGOOG > TITLE=MAINE IN THE NORTHEASTERN BOUNDARY CONTROVERSY	AUTHOR=BURRAGE, HENRY SWEETSER	ACCESS-DATE=JUNE 22, 2016, 78,	no change to map

!scope=row|December 3, 1818

Illinois Territory south of 42°30′ north was admitted as the twenty-first state, Illinois. The remainder of the territory, along with the unorganized territory that was recently part of Indiana Territory, was assigned to Michigan Territory.{{usstat>3	3|536}}	alt=Map of the change to the United States in central North America on December 3, 1818|250px)

“>

1819–1845 (Northwest expansion){|class“wikitable plainrowheaders”

!scope=“col“|Date!scope=“col“|Event!scope=“col“|Change Map!scope=row|January 30, 1819

Treaty of 1818 went into effect, setting 49th parallel north>49° north as the border with the United Kingdom of Great Britain and Ireland	west of the Lake of the Woods, and also establishing the Oregon Country as a shared region with the United Kingdom.Van Zandt, pp. 14–15{{usstat>8		PUBLISHER=UNITED STATES DEPARTMENT OF STATE	Russian America>Russian-held lands; this map uses the later-established line at 54°40′ north for simplicity.	(File:United States Central change 1819-01-30.png	250px)Northwestern North America:(File:United States Northwest change 1819-01-30.png	250px)

!scope=row|July 4, 1819

Arkansas Territory>Arkansaw Territory was organized from the southern slice of Missouri Territory.{{efn	Mississippi River meets 36th parallel north>36° north: west to the St. Francis River, up that to Parallel 36°30′ north	, then west.}}{{usstat>3|493}}Van Zandt, pp. 118–120	alt=Map of the change to the United States in central North America on July 4, 1819|250px)

!scope=row|December 14, 1819

Alabama Territory was admitted as the twenty-second state, Alabama.{{usstat>3	3|608}} The statehood act provided for a survey of the southern part of the border with Mississippi, which was intended to be north–south, for adjustment if it was discovered to encroach upon Mississippi’s established counties; it was later discovered to do so.	alt=Map of the change to the United States in central North America on December 14, 1819|250px)

!scope=row|March 15, 1820

Missouri Compromise, the District of Maine, the northern and separate part of Massachusetts, was admitted as the twenty-third state, Maine.{{usstat>3|544}}Van Zandt, pp. 55–60	alt=Map of the change to the United States in central North America on March 15, 1820|250px)

!scope=row|April 21, 1820

Arkansas Territory” being officially used instead of “Arkansaw Territory”.{{usstat>3|565}}	alt=Map of the change to the United States in central North America on April 21, 1820|250px)

!scope=row|May 12, 1820

Kentucky and Tennessee was established. To make up for the fact that the border between the Cumberland Gap and the Tennessee River veered north as much as almost 10 miles from Parallel 36°30′ north>36°30′ north, a new survey was conducted starting at that latitude on the Mississippi River and moving east to the Tennessee River, hence guaranteeing this last bit of border would fit the original ideal.

alt=Map of the change to the United States in central North America on May 12, 1820|250px)

!scope=row|July 19, 1820

Alabama and Mississippi was resolved, as per the act admitting Alabama as a state, because the provisional border encroached on Mississippi.THE OFFICIAL AND STATISTICAL REGISTER OF THE STATE OF MISSISSIPPI, VOLUME 4	PAGES=57–58	LAST1=ROWLAND	YEAR=1917, As the result of a survey, the southern border terminus was moved about 3.8 miles to the east, which changed the border up to the then-northwest corner of Alabama’s Washington County. The date when this happened is unclear; the sources available give either an unpublished report dated May 29, 1820, or the completion of the demarcation of the new line on July 19, 1820.	Change on paper only:(File:United States Central change 1820-07-19.png	250px)

!scope=row|December 19, 1820

Alabama redefined some county borders, ending its erroneous overlap of Mississippi created on February 6, 1818.ALABAMA LEGISLATURE	TITLE=ALABAMA LEGISLATIVE ACTS, 1820	PAGE=92,	Change on paper only:(File:United States Central change 1820-12-19.png	250px)

!scope=row|February 22, 1821|The Adams–Onís Treaty with Spain took effect.Van Zandt, pp. 26–27 The many changes included:

• The border with the holdings of Spain was concretely defined; previously, it had been the watershed of the Mississippi River and, for Oregon Country, the Columbia River, whereas now it followed specific rivers and parallels.{{efn|The new border was, from the Gulf of Mexico: up the Sabine River to 32° north; north to the Red River; up that to 100° west; north to the Arkansas River; up that to its source; north to 42° north; then west to the Pacific Ocean.}}
• The new border placed the “Neutral Ground” in Louisiana.
• Florida was ceded to the United States, although the formal transfer would not happen until July.
• Arkansas Territory had created Miller County south of the Red River, and this area was now on the Spanish side of the border. However, as this was a change made solely by the territory, and not by the federal government, in this map it is considered a domestic dispute.
• With Spanish West Florida being ceded, the dispute between it and Alabama, Louisiana, and Mississippi was resolved.

File:United States Central change 1821-02-22.png	250pxDisputes:(File:United States Central dispute change 1821-02-22.png	250px)

!scope=row|July 10, 1821

East Florida) was formally transferred to the United States by Spain.HTTPS://WWW.FLORIDAMEMORY.COM/BLOG/2012/07/17/9-THE-UNITED-STATES-FORMALLY-TAKES-CONTROL-OF-FLORIDA/ >TITLE=THE UNITED STATES FORMALLY TAKES CONTROL OF FLORIDA (JULY 17, 1821)	PUBLISHER=STATE LIBRARY AND ARCHIVES OF FLORIDA	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20150908071907/HTTP://WWW.FLORIDAMEMORY.COM/BLOG/2012/07/17/9-THE-UNITED-STATES-FORMALLY-TAKES-CONTROL-OF-FLORIDA/, September 8, 2015,	alt=Map of the change to the United States in central North America on July 10, 1821|250px)

!scope=row|July 17, 1821

Spanish West Florida>West Florida was formally transferred to the United States by Spain.	alt=Map of the change to the United States in central North America on July 17, 1821|250px)

!scope=row|August 10, 1821

Missouri Territory was admitted as the twenty-fourth state, Missouri, the rest becoming unorganized territory.{{efn>The new Missouri–federal border was, from the mouth of the Des Moines River: up the river to a point west of the Des Moines Rapids on the Mississippi River, west to a point north of the mouth of the Kansas River, then south.}}{{usstat	545}}	alt=Map of the change to the United States in central North America on August 10, 1821|250px)

!scope=row|March 30, 1822

East Florida) and Spanish West Florida	were organized as Florida Territory.{{usstat>3|654}}Van Zandt, pp. 104–105	alt=Map of the change to the United States in central North America on March 30, 1822|250px)

!scope=row|May 26, 1824

Arkansas Territory west of a line south from a point 40 miles west of Missouri’s western border was returned to unorganized territory.{{usstat>4|40}}	alt=Map of the change to the United States in central North America on May 26, 1824|250px)

!scope=row|January 12, 1825

Russo-American Treaty of 1824>treaty with the Russian Empire established parallel 54°40′ north	as the northern border of Oregon Country for American purposes; a separate treaty created the same border between Russia and the United Kingdom of Great Britain and Ireland>United Kingdom.HTTP://WWW.EXPLORENORTH.COM/LIBRARY/HISTORY/BL-RUSUS1825.HTM >TITLE=CONVENTION BETWEEN THE UNITED STATES OF AMERICA AND HIS MAJESTY THE EMPEROR OF ALL THE RUSSIAS, RELATIVE TO NAVIGATING, FISHING, ETC., IN THE PACIFIC OCEAN	URL-STATUS=LIVE	ARCHIVE-DATE=MARCH 19, 2016, As this was likely the de facto border anyway, the region is already mapped with this line.	no change to map

!scope=row|May 6, 1828

Cherokee moved the western border of Arkansas Territory, returning part of it to unorganized territory.{{efn>The new Arkansas Territory–federal border, from the north, a line from the southwestern corner of Missouri to a point on the Arkansas River “100 paces east” of Fort Smith, Arkansas	, as the border of the lands of the Choctaw>Eastern Choctaw, then south. However, the Arkansas Supreme Court determined in 1909 that the “100 paces east” was a clerical error, and that logically it should have said “100 paces west”.HTTPS://BOOKS.GOOGLE.COM/BOOKS?ID=IF02AQAAMAAJ > TITLE=ARKANSAS REPORTS: CASES DETERMINED IN THE SUPREME COURT OF ARKANSAS, VOLUME 93	YEAR=1910	LAST1=SUPREME COURT	LAST2=WILLIAMS	7|311}}	alt=Map of the change to the United States in central North America on May 6, 1828|250px)

!scope=row|January 20, 1831

William I of the Netherlands, having been asked per the Treaty of Ghent to arbitrate the disputed border between Maine and the United Kingdom of Great Britain and Ireland>United Kingdom, rendered his decision: since reconciling the treaty with the maps given was too difficult, he drew a compromise line. The British government accepted it, but Maine protested, and on January 19, 1832, the American government rejected it.Van Zandt, pp. 15-17

no change to map

!scope=row|July 9, 1832

New Hampshire north of the Connecticut Lakes, which was disputed with the United Kingdom of Great Britain and Ireland>United Kingdom, declared independence as the Republic of Indian Stream.JOURNAL, Keedy, Edwin R., January 1953, The Constitutions of the State of Franklin, the Indian Stream Republic and the State of Deseret, University of Pennsylvania Law Review, 101, 4, 3309935, 521–525, 10.2307/3309935,scholarship.law.upenn.edu/cgi/viewcontent.cgi?article=7935&context=penn_law_review, While tiny, it does appear to have maintained some control over its territory.	Disputes:(File:United States Central dispute change 1832-07-09.png	250px)

!scope=row|June 28, 1834

Michigan Territory gained a large parcel of land from unorganized territory, extending west to the Missouri River and White Earth River (North Dakota)>White Earth River.{{usstat	701}}	alt=Map of the change to the United States in central North America on June 28, 1834|250px)

!scope=row|August 5, 1835

Republic of Indian Stream recognized the jurisdiction of New Hampshire, thus ending its claimed independence. The date given is of a communication sent to United Kingdom of Great Britain and Ireland>British authorities;HTTPS://BOOKS.GOOGLE.COM/BOOKS?ID=HHWFAQAAMAAJ > TITLE=BRITISH AND FOREIGN STATE PAPERS	PAGE=444	LAST1=FOREIGN OFFICE, Great Britain, other sources note a resolution passed by the citizens of Indian Stream on April 2, 1836.	Disputes:(File:United States Central dispute change 1835-08-05.png	250px)

!scope=row|June 15, 1836

Arkansas Territory was admitted as the twenty-fifth state, Arkansas.{{usstat>5|50}}	alt=Map of the change to the United States in central North America on June 15, 1836|250px)

!scope=row|July 3, 1836

Wisconsin Territory was organized from the western bulk of Michigan Territory.{{efn>The new Michigan Territory–Wisconsin Territory border was, from Lake Superior: up the Montreal River (Wisconsin–Michigan)	to Lac Vieux Desert; a line to the source of the Menominee River; then down that to Green Bay (Lake Michigan)>Green Bay. However, this definition was impossible: The Montreal River ended long before it reached Lac Vieux Desert. The issue would be resolved in 1850.}}{{usstat	10}}Van Zandt, pp. 128–131 The two large peninsulas between the Great Lakes remained in Michigan Territory; the upper peninsula was included in exchange for the territory abandoning its claim to the Toledo Strip. The territory initially rejected this plan, but would accept it on December 14.	alt=Map of the change to the United States in central North America on July 3, 1836|250px)

!scope=row|December 14, 1836

Michigan Territory agreed to abandon its claim to the Toledo Strip, ending its dispute with Ohio.HTTPS://MITTENHISTORY.COM/2013/12/14/THE-FROSTBITTEN-CONVENTION-OR-HOW-MICHIGAN-ENDED-THE-TOLEDO-WAR-AND-BECAME-A-STATE/	ACCESS-DATE=JUNE 22, 2016	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160809123756/HTTPS://MITTENHISTORY.COM/2013/12/14/THE-FROSTBITTEN-CONVENTION-OR-HOW-MICHIGAN-ENDED-THE-TOLEDO-WAR-AND-BECAME-A-STATE/, August 9, 2016,	alt=Map of the change to the United States in central North America on December 14, 1836|250px)

!scope=row|January 26, 1837

Michigan Territory was admitted as the twenty-sixth state, Michigan.{{usstat>5|144}}	alt=Map of the change to the United States in central North America on January 26, 1837|250px)

!scope=row|March 28, 1837

Platte Purchase, obtained from several nations including the Potawatomi, Ioway, Missouria, Otoe, and Sac and Fox Nation>Sac and Fox,COMBS > FIRST=H. JASON	TITLE=THE PLATTE PURCHASE AND NATIVE AMERICAN REMOVAL	JOURNAL=PLAINS ANTHROPOLOGIST	ISSUE=182	DOI=10.1080/2052546.2002.11932095	Missouri, extending its northern border west to the Missouri River.{{usstat>5	5|802}}	alt=Map of the change to the United States in central North America on March 28, 1837|250px)

!scope=row|July 3, 1838

Iowa Territory was organized from Wisconsin Territory west of the Mississippi River.{{usstat>5|235}}Van Zandt, pp. 131–133	alt=Map of the change to the United States in central North America on July 3, 1838|250px)

!scope=row|February 11, 1839

Missouri claimed an area north of its Sullivan Line>border with Iowa Territory, initiating the long dispute known as the Honey War.An ACT defining the northern boundary line of this State, accessed March 16, 2023	alt=Map of the change to the United States in central North America on February 11, 1839|250px)

!scope=row|May 21, 1840

Republic of Texas>Texas concluded that the area claimed by Arkansas for Miller County, Arkansas Territory	belonged to Texas.{{usstat>5|674}}	(File:United States Central change 1840-05-21.png	250px)

!scope=row|November 10, 1842

Webster–Ashburton Treaty defined the border with the United Kingdom of Great Britain and Ireland>United Kingdom east of the Rocky Mountains.WEB ,avalon.law.yale.edu/19th_century/br-1842.asp , Text of “The Webster–Ashburton Treaty” , The Avalon Project at Yale Law School , December 3, 2023 , Van Zandt, pp. 17–18 One source also mentions it very slightly altering the maritime boundary between Michigan and Wisconsin Territory.WEB,www.lib.msu.edu/exhibits/map/minnsliver.jsp, Evolution of Michigan’s Boundaries: The Minnesota Sliver, Michigan State University, December 27, 2015, live,web.archive.org/web/20160108184914/https://www.lib.msu.edu/exhibits/map/minnsliver.jsp, January 8, 2016, The treaty resolved the disputes over the northern borders of Maine and New Hampshire,{{efn|The new northeastern border was, from Passamaquoddy Bay: up the St. Croix River to its source; north to the St. John River; up that to the St. Francis River; up that to its source outlet at Lake Pohenegamook; southwest to the northwest branch of the St. John River; a line from there to where the St. John River crosses 46°25’ north; up the river to its source; along the highlands to the source of Halls Stream, then down that to 45° north.}} the northeastern border of Wisconsin Territory,{{efn|The new northern border was, from Lake Superior: up the Pigeon River to the many lakes and rivers of the Boundary Waters, eventually reaching the Rainy River; then down that to the Lake of the Woods.}} and Sugar Island with Michigan.The border between New York and Vermont on the one side, and the United Kingdom on the other, was clarified by the treaty. In 1816, construction began on an unnamed fort nicknamed “Fort Blunder” on a peninsula in Lake Champlain that, while south of the surveyed border, was discovered to be north of 45° north, which was the border set by the Treaty of Paris and thus in British territory. Consequently, construction on the fort was abandoned. The Webster–Ashburton Treaty specified that section of the border was to follow the surveyed line, rather than the exact parallel, thus moving the fort’s area into the United States, and a new fort, Fort Montgomery, would be built on the spot in 1844.Text from Webster–Ashburton Treaty: “till the line thus run intersects the old line of boundary surveyed and marked by Valentine and Collins previously to the year 1774, as the 45th degree of north latitude, and which has been known and understood to be the line of actual division between the States of New York and Vermont on one side, and the British Province of Canada on the other” As the earlier line was surveyed, even though it did not match the definition, it was deemed to be the legitimate border.	(File:United States Central change 1842-11-10.png	250px)Disputes:(File:United States Central dispute change 1842-11-10.png	250px)

!scope=row|July 5, 1843

Provisional Government of Oregon>provisional government for Oregon Country. While not official, it did maintain some jurisdiction over the area.HTTPS://SOS.OREGON.GOV/ARCHIVES/RECORDS/PROVISIONAL-GUIDE/PAGES/OREGON-MAPS.ASPX >TITLE=PROVISIONAL AND TERRITORIAL RECORDS GUIDE – 1843 MAP	ACCESS-DATE=MARCH 12, 2016,	Unofficial change: (File:United States Central change 1843-07-05.png	250px)

!scope=row|March 3, 1845

Florida Territory was admitted as the twenty-seventh state, Florida.{{usstat>5|742}}	alt=Map of the change to the United States in central North America on March 3, 1845|250px)

“>

1845–1860 (Southwest expansion){|class“wikitable plainrowheaders”

!scope=“col“|Date!scope=“col“|Event!scope=“col“|Change Map!scope=row|December 29, 1845

Republic of Texas was Texas annexation>annexed and admitted as the twenty-eighth state, Texas, extending the United States southwest to the Rio Grande.{{usstat	108}}Van Zandt, pp. 120–127 All of Texas was claimed by Mexico. While many sources state that Mexico recognized the independence of the eastern portion of Texas, Treaties of Velasco	were rejected by the Mexican government. Texas formally handed over sovereignty to the United States in a ceremony on February 19, 1846.HTTPS://HISTORY.STATE.GOV/COUNTRIES/TEXAS	PUBLISHER=UNITED STATES STATE DEPARTMENT	URL-STATUS=LIVE	ARCHIVE-DATE=APRIL 1, 2017, The annexation led to the beginning of the Mexican–American War a few months later.	(File:United States Central change 1845-12-29.png	250px)Disputes:(File:United States Central dispute change 1845-12-29.png	250px)

!scope=row|June 15, 1846

Oregon Treaty established 49th parallel north>49° north west of the Lake of the Woods as the continental border (so it did not include Vancouver Island) with land held by the United Kingdom. The sharing of Oregon Country ended, and the United States portion became unorganized territory.WEB ,avalon.law.yale.edu/19th_century/br-1846.asp , Text of “Treaty with Great Britain, in Regard to Limits Westward of the Rocky Mountains” , The Avalon Project at Yale Law School , August 4, 2006 , live ,avalon.law.yale.edu/19th_century/br-1846.asp" title="web.archive.org/web/20090419184450avalon.law.yale.edu/19th_century/br-1846.asp">web.archive.org/web/20090419184450avalon.law.yale.edu/19th_century/br-1846.asp , April 19, 2009 , The treaty was vague on which strait should be the border between Vancouver Island and the continent, thus causing a dispute over ownership of the San Juan Islands. It specified “through the middle of the said channel and of Fuca Straits, to the Pacific Ocean”.	(File:United States Central change 1846-06-15.png	250px)Northwestern North America:(File:United States Northwest change 1846-06-15.png	250px)Disputes:(File:United States Central dispute change 1846-06-15.png	250px)

!scope=row|September 22, 1846

Capture of Santa Fe>capture on August 18, 1846, of Santa Fe, New Mexico

, the capital of the Mexico>Mexican territory of Santa Fe de Nuevo México,HTTPS://BOOKS.GOOGLE.COM/BOOKS?ID=4SOSESWVAEEC&PG=PA129 > TITLE=A JOURNEY THROUGH NEW MEXICO HISTORY

ACCESS-DATE=MARCH 16, 2016

PAGE=129

ISBN=978-0-86534-541-6, a code of laws known as the Kearny Code was created for the area.HTTP://AVALON.LAW.YALE.EDU/19TH_CENTURY/KEARNEY.ASP >TITLE=NEW MEXICO – LAWS FOR THE GOVERNMENT OF THE TERRITORY OF NEW MEXICO; SEPTEMBER 22, 1846

PUBLISHER=THE AVALON PROJECT AT YALE LAW SCHOOL

ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160401184136/HTTP://AVALON.LAW.YALE.EDU/19TH_CENTURY/KEARNEY.ASP

YEAR=1850

URL-STATUS=LIVE

ARCHIVE-DATE=AUGUST 18, 2016, The region overlapped with Texas’ claim, though Texas had little to no control over the area outside of its eastern quarter.

Unofficial change:(File:United States Central change 1846-09-22.png

250px)

!scope=row|December 28, 1846

Iowa Territory south of 43°30′ north and east of the Big Sioux River was admitted as the twenty-ninth state, Iowa. The remainder became unorganized territory.{{usstat>9|117}}	alt=Map of the change to the United States in central North America on December 28, 1846|250px)

!scope=row|March 13, 1847

District of Columbia Retrocession (District of Columbia)>retroceded Alexandria County, District of Columbia	back to Virginia.Van Zandt, pp. 88–92 Congress passed the act on July 9, 1846,{{usstat>9	9	An ACT to extend the jurisdiction of the commonwealth of Virginia over the county of Alexandria {{webarchive>url=https://web.archive.org/web/20160510045250books.google.com/books?id=arlOAQAAIAAJ&lpg=PA41&ots=gqgVPUPY25&pg=PA41 |date=May 10, 2016 }}	alt=Map of the change to the United States in central North America on March 13, 1847|250px)

!scope=row|May 29, 1848

Wisconsin Territory was admitted as the thirtieth state, Wisconsin.{{efn>The new Wisconsin–Wisconsin Territory border was, from Lake Superior: up the St. Louis River to its first rapids; south to the St. Croix River (Wisconsin–Minnesota)	; then down that to the Mississippi River.}} The remainder became unorganized territory.{{usstat>9	de facto continuation of Wisconsin Territory.HTTPS://ARCHIVE.ORG/DETAILS/HENRYHASTINGSSIB00WILLRICH	YEAR=1894	277–281 >AUTHOR=WILLIAMS, J. FLETCHER	ACCESS-DATE=DECEMBER 28, 2015	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160307002027/HTTPS://ARCHIVE.ORG/DETAILS/HENRYHASTINGSSIB00WILLRICH, March 7, 2016,	alt=Map of the change to the United States in central North America on May 29, 1848|250px)

!scope=row|July 4, 1848

Treaty of Guadalupe Hidalgo ended the Mexican–American War and ceded a Mexican Cession>large parcel of land from Mexico, consisting of its territories of Alta California and Santa Fe de Nuevo México, and its claim to Texas.{{efn	Rio Grande: along the southern and western border of New Mexico until it meets the Gila River; down that to the Colorado River; then a line to a point one league south of the port of San Diego. However, the southern border of New Mexico was in question, with the US claim being 31°52′ north, and the Mexican claim being 32°22′ north.}}{{usstat>9|922}} A border dispute began over a disagreement about the southern border of Santa Fe de Nuevo México.Van Zandt, pp. 28–29	(File:United States Central change 1848-07-04.png	250px)Disputes:(File:United States Central dispute change 1848-07-04.png	250px)

!scope=row|August 14, 1848

Oregon Territory was organized from the unorganized territory that was formerly part of Oregon Country.{{usstat>9|323}}Van Zandt, pp. 153–155	alt=Map of the change to the United States in central North America on August 14, 1848|250px)

!scope=row|February 13, 1849

Iowa and Missouri known as the Honey War was Missouri v. Iowa>resolved by the Supreme Court of the United States. The resulting border was the Sullivan Line that existed before the dispute, roughly splitting the two claims.{{ussc	volume=48	year=1849}}	alt=Map of the change to the United States in central North America on February 13, 1849|250px)

!scope=row|March 3, 1849

Minnesota Territory was organized from the region that had been operating as de facto Wisconsin Territory, and unorganized territory east of the Missouri River>Missouri and White Earth River (North Dakota)	Rivers.{{usstat>9|403}}Van Zandt, pp. 133–134	alt=Map of the change to the United States in central North America on March 3, 1849|250px)

!scope=row|March 12, 1849

State of Deseret and claimed a vast portion of the southwest, including most of the Mexican Cession. Though it petitioned to be admitted to the United States, the proposal was rejected and, in 1850, Utah Territory was formed instead.YOUNG, BRIGHAM	PAGE=675	URL=HTTPS://BOOKS.GOOGLE.COM/BOOKS?ID=UCRZAWAAQBAJ&PG=PA675	LAST1=DANVER	DATE=APRIL 25, 2013, The claimed area overlapped slightly with Texas’ claimed area, as well as part of Oregon Territory.	Unofficial change:(File:United States Central change 1849-03-12.png	250px)

!scope=“row“|November 24, 1849

Texas, with consent from the United States Congress,{{usstat>9	Louisiana from the west bank of the Sabine River (Texas–Louisiana)>Sabine River to the middle of the river.BOUNDARIES > URL=HTTPS://TSHAONLINE.ORG/HANDBOOK/ONLINE/ARTICLES/MGB02	PUBLISHER=TEXAS STATE HISTORICAL ASSOCIATION		YEAR=1949	JSTOR=30240685	VOLUME=53	PAGES=1–18, {{ussc	1}}	no change to map

!scope=row|September 9, 1850

Mexican Cession was admitted as the thirty-first state, California.{{efn>The new California–federal border was, from the north: south along 120th meridian west	to 39th parallel north>39° north; a line to where the Colorado River intersects 35th parallel north	; then down the Colorado River.}}Van Zandt, pp. 151–153{{usstat>9	37th parallel north>37° north and west of the summit of the Rocky Mountains was organized as Utah Territory.{{usstat	453}}Van Zandt, pp. 159–160 Part of Utah Territory overlapped with the portion of Texas that would be purchased on December 13, 1850, but the law authorizing the purchase was passed on this day, so the borders of Utah Territory assumed that the purchase would go through.	alt=Map of the change to the United States in central North America on September 9, 1850|250px)

!scope=row|December 9, 1850

United Kingdom of Great Britain and Ireland>United Kingdom ceded less than one acre of underwater rock for a Horseshoe Reef Lighthouse	in Lake Erie near Buffalo, New York; although it was on Middle Reef, it was named for the nearby Horseshoe Reef.BUFFALO WATER INTAKE, HORSESHOE REEF LIGHT HISTORICAL MARKER	ACCESS-DATE=2024-03-25	LANGUAGE=EN, It was surrounded by British waters, thus creating a form of enclave.Treaty between the United States of America and the United Kingdom Concerning the Boundary between the United States and the Dominion of Canada from the Atlantic Ocean to the Pacific Ocean, signed April 11, 1908; accessed June 30, 2015	alt=Map of the change to the United States in central North America on December 9, 1850|250px)

!scope=row|December 13, 1850

Texas.{{efn>The new Texas–federal border was, from the south: up the Rio Grande to 32nd parallel north	; east to 103rd meridian west>103° west; north to Parallel 36°30′ north	; then east.}} New Mexico Territory was organized from the part of this land east of the Rio Grande, along with the remaining unorganized territory from the Mexican Cession.{{efn>The borders of New Mexico Territory were, from where its border with Texas ended at 36°30′ north and 103° west: north to 38th parallel north	; west to the summit of the San Juan Mountains (called then the Sierra Madre); south along the ridge to 37th parallel north>37° north; then west.}}{{usstat	446}}Van Zandt, pp. 160–165 New Mexico Territory included all of the area that had been governed under the Kearny Code.	alt=Map of the change to the United States in central North America on December 13, 1850|250px)

!scope=row|April 5, 1851

State of Deseret dissolved itself, its functions and territory largely having been superseded by Utah Territory.HTTPS://ARCHIVE.ORG/DETAILS/LAWSORDINANCESOF00DESE	PUBLISHER=SHEPARD BOOK CO.	ACCESS-DATE=JUNE 22, 2016	AUTHOR1=DESERET,	Unofficial change:(File:United States Central change 1851-04-05.png	250px)

!scope=row|March 2, 1853

Washington Territory was organized from the half of Oregon Territory north of 46th parallel north>46° north and the Columbia River.{{usstat	172}}Van Zandt, pp. 155–156	alt=Map of the change to the United States in central North America on March 2, 1853|250px)

!scope=row|May 30, 1854

Kansas Territory was organized from unorganized territory north of 37th parallel north>37° north, and Nebraska Territory was organized north of 40th parallel north	.{{usstat>10	100th meridian west>100° west, became known as Indian Territory, designated as a place to resettle Indian tribes.A small strip between the Texas Panhandle and Kansas Territory was unclaimed because it fell south of Kansas Territory’s border but north of 36°30′ north, which had been established in the Missouri Compromise as the northern limit of slavery, and thus Texas could not have it. This became known as the Public Land Strip, or sometimes “No Man’s Land”.Kenneth R. Turner, “No Man’s Land”, {{webarchive|url=https://web.archive.org/web/20150402160744www.okhistory.org/publications/enc/entry.php?entry=NO001 |date=April 2, 2015}} Encyclopedia of Oklahoma History and Culture, www.okhistory.org (accessed June 4, 2015).	alt=Map of the change to the United States in central North America on May 30, 1854|250px)

!scope=row|June 30, 1854

Mexico known as the Gadsden Purchase, as it offered a much better route for a southern transcontinental railroad.{{efn>The new international border was, starting from where the Rio Grande crosses 31°47′ north: west 100 miles; south to 31°20′ north; west to 111th meridian west	; a line to a point on the Colorado River 20 miles below the mouth of the Gila River; then up the Colorado River.}}Van Zandt, p. 29HTTP://AVALON.LAW.YALE.EDU/19TH_CENTURY/MX1853.ASP	PUBLISHER=THE AVALON PROJECT AT YALE LAW SCHOOL	URL-STATUS=LIVE	ARCHIVE-DATE=MAY 19, 2015, This resolved the border dispute, since the disputed land was included in the purchase.	(File:United States Central change 1854-06-30.png	250px)Disputes:(File:United States Central dispute change 1854-06-30.png	250px)

!scope=row|August 4, 1854

Gadsden Purchase was assigned to New Mexico Territory.{{usstat>10|575}}	alt=Map of the change to the United States in central North America on August 4, 1854|250px)

!scope=row|January 11, 1855

Boston Corner, New York>Boston Corner was transferred from Massachusetts to New York (state)	because it was inaccessible from the rest of the Massachusetts.{{usstat>10		ACCESS-DATE=JULY 9, 2015	YEAR=1884,	alt=Map of the change to the United States in central North America on January 11, 1855|250px)

!scope=row|March 6, 1855

Florida in a boundary dispute with Georgia (U.S. state)>Georgia, setting the state boundary line along Florida v. Georgia (1855)	.FLORIDA V. GEORGIA (1855)	>VOL=58	OPINION=478	COURT=US	URL=HTTP://SUPREME.JUSTIA.COM/US/58/478/CASE.HTML,	no change to map

!scope=row|October 28, 1856|Baker Island and Jarvis Island were claimed under the Guano Islands Act.

Pacific Ocean:(File:United States Pacific change 1856-10-28.png	250px)

!scope=row|May 11, 1858

Minnesota Territory was admitted as the thirty-second state, Minnesota.{{efn>The new Minnesota–federal border was, from the north: up the Red River of the North	to the Bois de Sioux River; up that to Lake Traverse and its southern tip; a line to Big Stone Lake and through that to its southern tip; then south.}} The remainder became unorganized territory.{{usstat>11|285}}	alt=Map of the change to the United States in central North America on May 11, 1858|250px)

!scope=row|August 31, 1858|Navassa Island was claimed under the Guano Islands Act.

Caribbean Sea:(File:United States Caribbean change 1858-08-31.png	250px)

!scope=row|December 3, 1858|Howland Island was claimed under the Guano Islands Act.

Pacific Ocean:(File:United States Pacific change 1858-12-03.png	250px)

!scope=row|February 14, 1859

Oregon Territory was admitted as the thirty-third state, Oregon.{{efn>The new Oregon–Washington Territory border was, from the north, up the Snake River to the mouth of the Owyhee River, then south.}} The remainder was transferred to Washington Territory.{{usstat	383}}	alt=Map of the change to the United States in central North America on February 14, 1859|250px)

!scope=row|July 6, 1859

Kentucky and Tennessee. It is unknown exactly why this was done, though one theory is a local landowner wanted his property in Tennessee.THE KENTUCKY ENCYCLOPEDIA	URL=HTTPS://BOOKS.GOOGLE.COM/BOOKS?ID=8EFSK4O--M0C&Q=SIMPSON+COUNTY+OFFSET&PG=PA635	PAGE=635	LAST1=KLEBER	YEAR=1992, HTTP://WWW.SITEMASON.COM/FILES/KUEC92/TNKYBORDER.PDF >TITLE=TENNESSEE-KENTUCKY BORDER DIDN’T TURN OUT AS STRAIGHT AS IT WAS SUPPOSED TO BE	URL-STATUS=LIVE	ARCHIVE-DATE=MARCH 4, 2016,	alt=Map of the change to the United States in central North America on July 6, 1859|250px)

!scope=row|September 6, 1859

Johnston Atoll was claimed under the Guano Islands Act, though it had been claimed by Kingdom of Hawaii>Hawaii in 1858.	Pacific Ocean:(File:United States Pacific change 1859-09-06.png	250px)

!scope=row|November 7, 1859

Kansas Territory>Kansas, Nebraska Territory	, New Mexico Territory>New Mexico, Utah Territory	, and Washington Territory>Washington, with the name of Jefferson Territory.{{efn	37th parallel north>37° north, 43rd parallel north	, 102nd meridian west>102° west, and 110th meridian west	.}} While never recognized by the federal government, it generally held control over the area until Colorado Territory was established, which adopted most of its laws.1832884	JOURNAL = THE AMERICAN HISTORICAL REVIEW	ISSUE = 1	LAST1 = PAXSON	YEAR = 1906, 10.2307/1832884,	Unofficial change:(File:United States Central change 1859-11-07.png	250px)

!scope=row|December 27, 1859

Enderbury Island, McKean Island, Rawaki Island>Phoenix Island, and Starbuck Island were claimed under the Guano Islands Act.	Pacific Ocean:(File:United States Pacific change 1859-12-27.png	250px)

!scope=row|December 29, 1859

Kiritimati>Christmas Island and Malden Island were claimed under the Guano Islands Act.	Pacific Ocean:(File:United States Pacific change 1859-12-29.png	250px)

!scope=row|February 8, 1860

Texas created Greer County, Texas>Greer County, claiming part of Indian Territory based on a different understanding from the federal government of which fork of the Red River was the border between the two.Atafu, Birnie Island, Butaritari, Caroline Island, Fanning Island, Flint Island, Gardner Island, Canton Island, Kingman Reef, Manihiki, Marakei, Nukunono, Palmyra Atoll, Penrhyn, Pukapuka, Rakahanga, Swains Island, Sydney Island, Vostok Island, and Washington Island were all claimed under the Guano Islands Act. Many additional islands were listed as bonded on this date, but based on the coordinates they were either phantoms or duplicates. In addition, Sarah Ann Island was claimed, which may have existed and would be sighted as late as 1917, but has since disappeared.NEWS,news.google.com/newspapers?nid=110&dat=19321016&id=34VOAAAAIBAJ&pg=2584,3552314, Vanishing of Sarah Ann, Tiny Pacific Island, Causes Scientists Much Worry, October 16, 1932, Lundington Daily News, 1, Washington, January 13, 2010,	(File:United States Central change 1860-02-08.png	250px)Pacific Ocean:(File:United States Pacific change 1860-02-08.png	250px)

“>

1860–1865 (Civil War){|class“wikitable plainrowheaders”

!scope=“col“|Date!scope=“col“|Event!scope=“col“|Change Map!scope=row|December 20, 1860

1860 United States presidential election>election of Abraham Lincoln, South Carolina proclaimed its secession from the Union, withdrawing from the Congress of the United States.	(File:United States Central change 1860-12-20.png	250px)Disputes:(File:United States Central dispute change 1860-12-20.png	250px)

!scope=row|January 9, 1861|Mississippi proclaimed its secession from the Union, withdrawing from Congress.

(File:United States Central change 1861-01-09.png	250px)Disputes:(File:United States Central dispute change 1861-01-09.png	250px)

!scope=row|January 10, 1861|Florida proclaimed its secession from the Union, withdrawing from Congress.

(File:United States Central change 1861-01-10.png	250px)Disputes:(File:United States Central dispute change 1861-01-10.png	250px)

!scope=row|January 11, 1861|Alabama proclaimed its secession from the Union, withdrawing from Congress.

(File:United States Central change 1861-01-11.png	250px)Disputes:(File:United States Central dispute change 1861-01-11.png	250px)

!scope=row|January 19, 1861

Georgia (U.S. state)>Georgia proclaimed its secession from the Union, withdrawing from Congress.	(File:United States Central change 1861-01-19.png	250px)Disputes:(File:United States Central dispute change 1861-01-19.png	250px)

!scope=row|January 26, 1861

Louisiana proclaimed its secession from the Union, withdrawing from Congress. However, the Louisiana’s 1st congressional district>1st and 2nd congressional districts, around New Orleans, maintained representation in Congress.	(File:United States Central change 1861-01-26.png	250px)Disputes:(File:United States Central dispute change 1861-01-26.png	250px)

!scope=row|January 29, 1861

Kansas Territory east of 25th meridian west from Washington>25° west from Washington was admitted as the thirty-fourth state, Kansas. The remainder became unorganized territory.{{usstat	126}}	alt=Map of the change to the United States in central North America on January 29, 1861|250px)

!scope=row|February 8, 1861

Confederate States of America was formed by representatives of the seceded states of Alabama, Georgia (U.S. state)>Georgia, Florida, Louisiana, Mississippi, and South Carolina.Constitution for the Provisional Government of the Confederate States of America {{webarchive	docsouth.unc.edu/imls/19conf/19conf.html >date=August 20, 2016 }}, accessed July 8, 2015	Disputes:(File:United States Central dispute change 1861-02-08.png	250px)

!scope=row|February 28, 1861

Colorado Territory was organized from portions of Nebraska Territory, New Mexico Territory, and Utah Territory, along with unorganized territory.{{efn>The borders of Colorado Territory were parallels 32nd parallel north	, 37th parallel north>37° north, and Washington meridians 25th meridian west from Washington	and 32nd meridian west from Washington>32° west.}}{{usstat	172}}Van Zandt, pp. 141–144	alt=Map of the change to the United States in central North America on February 28, 1861|250px)

!scope=row|March 2, 1861

Texas proclaimed its secession from the Union and was admitted to the Confederate States of America>Confederate States,An Act to admit Texas as a member of the Confederate States of America {{webarchive	docsouth.unc.edu/imls/19conf/19conf.html >date=August 20, 2016 }}, accessed July 8, 2015 withdrawing from Congress.Dakota Territory was organized from Nebraska Territory and the unorganized territory north of it.{{efn|The new Nebraska Territory–Dakota Territory border was, from the east: up the Missouri River to the Niobrara River; up that to the Keya Paha River; up that to 43° north; then west.}} Nebraska Territory’s western border was moved to 33° west from Washington, gaining small portions of Utah Territory and Washington Territory.{{usstat|12|239}}Van Zandt, pp. 134–136 Nevada Territory was organized from Utah Territory west of 39° west from Washington.{{usstat|12|209}}Van Zandt, pp. 158–159	(File:United States Central change 1861-03-02.png	250px)Disputes:(File:United States Central dispute change 1861-03-02.png	250px)

!scope=row|March 28, 1861

New Mexico Territory proclaimed an independent Confederate Arizona>Arizona Territory south of 34th parallel north	.HTTPS://WWW.NPS.GOV/CWINDEPTH/STATEBYSTATE/ARIZONA.HTML	ACCESS-DATE=APRIL 5, 2017	NATIONAL PARK SERVICE >URL-STATUS=LIVE	ARCHIVE-DATE=APRIL 6, 2017,	Disputes:(File:United States Central dispute change 1861-03-28.png	250px)

!scope=row|April 17, 1861

Battle of Fort Sumter and President Abraham Lincoln’s President Lincoln’s 75,000 volunteers>call for troops to respond, Virginia proclaimed its secession from the Union, withdrawing from Congress. However, the Virginia’s 1st congressional district	(along the Eastern Shore of Virginia>Eastern Shore), Virginia’s 7th congressional district	(near Washington, D.C.), and Virginia’s 10th congressional district>10th, Virginia’s 11th congressional district	, and Virginia’s 12th congressional district>12th (in the northwest of the state) congressional districts maintained representation in Congress.	(File:United States Central change 1861-04-17.png	250px)Disputes:(File:United States Central dispute change 1861-04-17.png	250px)

!scope=row|May 6, 1861|Arkansas proclaimed its secession from the Union, withdrawing from Congress.

(File:United States Central change 1861-05-06.png	250px)Disputes:(File:United States Central dispute change 1861-05-06.png	250px)

!scope=row|May 7, 1861

Virginia was admitted to the Confederate States of America>Confederate States.An Act to admit the Commonwealth of Virginia as a member of the Confederate States of America {{webarchive	docsouth.unc.edu/imls/19conf/19conf.html >date=August 20, 2016 }}, accessed July 8, 2015	Disputes:(File:United States Central dispute change 1861-05-07.png	250px)

!scope=row|May 16, 1861

Kentucky Kentucky Declaration of Neutrality>declared itself neutral in the American Civil War.	no change to map

!scope=row|May 20, 1861

Arkansas was admitted to the Confederate States of America>Confederate States.An Act to admit the State of Arkansas into the Confederacy {{webarchive	docsouth.unc.edu/imls/19conf/19conf.html >date=August 20, 2016 }}, accessed July 8, 2015North Carolina proclaimed its secession from the Union, withdrawing from Congress.	(File:United States Central change 1861-05-20.png	250px)Disputes:(File:United States Central dispute change 1861-05-20.png	250px)

!scope=row|May 21, 1861

North Carolina was admitted to the Confederate States of America>Confederate States. The law admitting the state required a presidential proclamation before it was to take effect,An Act to admit the State of North Carolina into the Confederacy, on a certain condition {{webarchive	docsouth.unc.edu/imls/19conf/19conf.html >date=August 20, 2016 }}, accessed June 29, 2016 which sources say took place on this date;HTTP://NORTHCAROLINAHISTORY.ORG/ENCYCLOPEDIA/SECESSION/ > TITLE=SECESSION, John Locke Foundation, the only primary source found so far is a statement from Jefferson Davis on July 20 stating that the proclamation had been made.Confederate Congress 1861, 1:272. (View the page cited)	Disputes:(File:United States Central dispute change 1861-05-21.png	250px)

!scope=row|June 6, 1861|Robert Williamson Steele, governor of Jefferson Territory, declared the territory disbanded and handed over the government to the first governor of Colorado Territory.

Unofficial change:(File:United States Central change 1861-06-06.png	250px)

!scope=row|June 8, 1861

Tennessee proclaimed its secession from the Union, withdrawing from Congress.HTTP://WWW.DIGITALHISTORY.UH.EDU/DISP_TEXTBOOK.CFM?SMTID=3&PSID=3953	PUBLISHER=UNIVERSITY OF HOUSTON	URL-STATUS=LIVE	ARCHIVE-DATE=SEPTEMBER 5, 2015, However, the Tennessee’s 2nd congressional district	, Tennessee’s 3rd congressional district>3rd, and 4th congressional districts in the central part of the state maintained representation in Congress.	(File:United States Central change 1861-06-08.png	250px)Disputes:(File:United States Central dispute change 1861-06-08.png	250px)

!scope=row|June 25, 1861

Restored Government of Virginia in Wheeling, West Virginia>Wheeling as the legitimate government of Virginia.HTTPS://WWW.NYTIMES.COM/1864/06/26/NEWS/VIRGINIA-THE-RESTORED-GOVERNMENT-OF-VIRGINIA-HISTORY-OF-THE-NEW-STATE-OF-THINGS.HTML?PAGEWANTED=ALL >WORK=THE NEW YORK TIMES	DATE=JUNE 26, 1864	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160812201924/HTTP://WWW.NYTIMES.COM/1864/06/26/NEWS/VIRGINIA-THE-RESTORED-GOVERNMENT-OF-VIRGINIA-HISTORY-OF-THE-NEW-STATE-OF-THINGS.HTML?PAGEWANTED=ALL, August 12, 2016,	(File:United States Central change 1861-06-25.png	250px)

!scope=row|July 2, 1861

Tennessee was admitted to the Confederate States of America>Confederate States.HTTPS://BOOKS.GOOGLE.COM/BOOKS?ID=APS7AQAAMAAJ > TITLE=OFFICIAL RECORDS OF THE UNION AND CONFEDERATE NAVIES IN THE WAR OF THE REBELLION	ACCESS-DATE=JUNE 22, 2016	LAST1=NAVY DEPT	LAST2=RUSH, Richard,	Disputes:(File:United States Central dispute change 1861-07-02.png	250px)

!scope=row|August 1, 1861

First Battle of Mesilla, Confederate Arizona>Arizona Territory was proclaimed as part of the Confederate States of America	.THE CIVIL WAR IN THE WESTERN TERRITORIES	FIRST=RAY CHARLES	PUBLISHER=UNIVERSITY OF OKLAHOMA PRESS	PAGES=122–123	ACCESS-DATE=AUGUST 3, 2010,	Disputes:(File:United States Central dispute change 1861-08-01.png	250px)

!scope=row|September 13, 1861

Columbus, Kentucky>Columbus, Kentucky, on September 3, 1861, the state abandoned neutrality and aligned with the Union government.KY Acts 1861 p. 110 {{webarchive	books.google.com/books?id=zzhNAQAAMAAJ&pg=PA110 >date=December 21, 2016 }}	no change to map

!scope=row|October 31, 1861|A splinter government in Neosho, Missouri, proclaimed the secession of the state from the United States.

Disputes:(File:United States Central dispute change 1861-10-31.png	250px)

!scope=row|November 20, 1861

Russellville, Kentucky, proclaimed the formation of a splinter government in Bowling Green, Kentucky>Bowling Green and the secession of Kentucky from the United States.	Disputes:(File:United States Central dispute change 1861-11-20.png	250px)

!scope=row|November 28, 1861

Confederate government of Missouri>Neosho government of Missouri was admitted to the Confederate States. The Confederate States never held much power over the state, but it was given full representation in the legislature.Confederate Public Law Session V, Chapter I; accessed May 22, 2015	Disputes:(File:United States Central dispute change 1861-11-28.png	250px)

!scope=row|December 10, 1861

Confederate government of Kentucky>Bowling Green government of Kentucky was admitted to the Confederate States of America	. The Confederate States never held much power over the state, but it was given full representation in the legislature.Confederate Public Law Session V, Chapter V {{webarchive>url=https://web.archive.org/web/20160421231551books.google.com/books?id=eMhthJ3G9ykC&lpg=PR12pg%3DPA222 |date=April 21, 2016 }}; accessed May 22, 2015	Disputes:(File:United States Central dispute change 1861-12-10.png	250px)

!scope=row|December 21, 1861

Confederate States of America>Confederate States ratified treaties with the Osage Nation	, and the Seneca people>Seneca and Shawnee.HTTP://TREATIESPORTAL.UNL.EDU/CSAINDIANTREATIES/ >TITLE=AS LONG AS GRASS SHALL GROW AND WATER RUN: THE TREATIES FORMED BY THE CONFEDERATE STATES OF AMERICA AND THE TRIBES IN INDIAN TERRITORY, 1861	UNIVERSITY OF NEBRASKA–LINCOLN >ACCESS-DATE=MAY 2, 2017	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20161024162044/HTTP://TREATIESPORTAL.UNL.EDU/CSAINDIANTREATIES/		DATE=28 OCTOBER 2010	URL-STATUS=LIVE	ARCHIVE-DATE=APRIL 14, 2017,	Disputes:(File:United States Central dispute change 1861-12-21.png	250px)

!scope=row|December 23, 1861

Confederate States of America>Confederate States ratified treaties with the Cherokee Nation	, granting them a delegate to the Congress of the Confederate States, and with the Seminole Nation>Seminole, granting them a delegate to be shared with the Creek.	Disputes:(File:United States Central dispute change 1861-12-23.png	250px)

!scope=row|December 31, 1861

Confederate States of America>Confederate States ratified treaties with the Choctaw and Chickasaw, granting them a delegate in the Congress of the Confederate States; with the Comanche; with the Creek Nation	, granting them a delegate to be shared with the Seminole Nation>Seminole; and the Quapaw.	Disputes:(File:United States Central dispute change 1861-12-31.png	250px)

!scope=row|March 1, 1862

Supreme Court of the United States took effect, modifying the border between Massachusetts and Rhode Island.{{efn>The decree transferred land from the left bank of the Blackstone River to Rhode Island, including what is now East Providence, Rhode Island	, in exchange land around Fall River, Massachusetts>Fall River being transferred to Massachusetts.}}{{usstat	382}}	alt=Map of the change to the United States in central North America on March 1, 1862|250px)

!scope=row|April 15, 1862

Palmyra Atoll was annexed by Kingdom of Hawaii>Hawaii, and the American claim falls dormant.HTTPS://WWW.DOI.GOV/OIA/ISLANDS/PALMYRAATOLL >PUBLISHER=OFFICE OF INSULAR AFFAIRS	DATE=11 JUNE 2015	URL-STATUS=LIVE	ARCHIVE-DATE=SEPTEMBER 10, 2015,	Pacific Ocean:(File:United States Pacific change 1862-04-15.png	250px)

!scope=row|July 14, 1862

Utah Territory west of 38° Washington meridians>west from Washington was transferred to Nevada Territory.{{usstat	575}}	alt=Map of the change to the United States in central North America on July 14, 1862|250px)

!scope=row|December 30, 1862

Swan Islands, Honduras>Swan Islands were claimed under the Guano Islands Act.	Caribbean Sea:(File:United States Caribbean change 1862-12-30.png	250px)

!scope=row|February 24, 1863

Arizona Territory was organized from the half of New Mexico Territory west of 32nd meridian west from Washington>32° west from Washington.Van Zandt, p. 165{{usstat	664}}	alt=Map of the change to the United States in central North America on February 24, 1863|250px)

!scope=row|March 3, 1863

Idaho Territory was organized from the parts of Dakota Territory and Nebraska Territory west of 27th meridian west from Washington>27° west from Washington, and the half of Washington Territory east of the Snake River and a line north from the mouth of the Clearwater River (Idaho)	.{{usstat>12|808}}Van Zandt, pp. 156–158	alt=Map of the change to the United States in central North America on March 3, 1863|250px)

!scope=row|March 4, 1863

United States House of Representatives held by the Unionist areas of Louisiana, Tennessee, and Virginia, effectively expelling the states.Martis, Kenneth C., “Historical Atlas of Political Parties in the United States Congress: 1789-1989, 1989 {{ISBN>0-02-920170-5}} p. 116.	alt=Map of the change to the United States in central North America on March 4, 1863|250px)

!scope=row|June 20, 1863

Virginia, represented by the Restored Government of Virginia in Wheeling, West Virginia>Wheeling, were split from the rest of Virginia and admitted to the Union as the thirty-fifth state, West Virginia.{{efn

Barbour County, West Virginia>Barbour, Boone County, West Virginia

, Braxton County, West Virginia>Braxton, Brooke County, West Virginia

, Cabell County, West Virginia>Cabell, Calhoun County, West Virginia

, Clay County, West Virginia>Clay, Doddridge County, West Virginia

, Fayette County, West Virginia>Fayette, Gilmer County, West Virginia

, Greenbrier County, West Virginia>Greenbrier, Hampshire County, West Virginia

, Hancock County, West Virginia>Hancock, Hardy County, West Virginia

, Harrison County, West Virginia>Harrison, Jackson County, West Virginia

, Kanawha County, West Virginia>Kanawha, Lewis County, West Virginia

, Logan County, West Virginia>Logan, McDowell County, West Virginia

, Marion County, West Virginia>Marion, Marshall County, West Virginia

, Mason County, West Virginia>Mason, Mercer County, West Virginia

, Monongalia County, West Virginia>Monongalia, Monroe County, West Virginia

, Morgan County, West Virginia>Morgan, Nicholas County, West Virginia

, Ohio County, West Virginia>Ohio, Pendleton County, West Virginia

, Pleasants County, West Virginia>Pleasants, Pocahontas County, West Virginia

, Preston County, West Virginia>Preston, Putnam County, West Virginia

, Raleigh County, West Virginia>Raleigh, Randolph County, West Virginia

, Ritchie County, West Virginia>Ritchie, Roane County, West Virginia

, Taylor County, West Virginia>Taylor, Tucker County, West Virginia

, Tyler County, West Virginia>Tyler, Upshur County, West Virginia

, Wayne County, West Virginia>Wayne, Webster County, West Virginia

, Wetzel County, West Virginia>Wetzel, Wirt County, West Virginia

, Wood County, West Virginia>Wood, and Wyoming County, West Virginia

.}}{{usstat>13

Alexandria, Virginia>Alexandria.

alt=Map of the change to the United States in central North America on June 20, 1863|250px)

!scope=row|August 5, 1863

Berkeley County, West Virginia>Berkeley County was transferred by the federal government from Virginia to West Virginia.W.Va. Acts 1863, 1st sess., ch. 35, sec. 1/pp. 33–35 {{webarchive	books.google.com/books?id=QRtEAAAAYAAJ&lpg=RA1-PA103&ots=x_zuvvEvgk&pg=RA3-PA33 >date=April 6, 2016 }}	alt=Map of the change to the United States in central North America on August 5, 1863|250px)

!scope=row|November 2, 1863

Jefferson County, West Virginia>Jefferson County was transferred from Virginia to West Virginia.W.Va. Acts 1863, 1st sess., ch. 90, sec. 1/pp. 103–105 {{webarchive	books.google.com/books?id=QRtEAAAAYAAJ&lpg=RA1-PA103&ots=x_zuvvEvgk&pg=RA1-PA103 >date=May 22, 2016 }}	alt=Map of the change to the United States in central North America on November 2, 1863|250px)

!scope=row|May 26, 1864

Montana Territory was organized from the northeast third of Idaho Territory,{{efn>The new Idaho Territory–Montana Territory border was, from the north: south along 39th meridian west from Washington	to the crest of the Bitterroot Range and the Rocky Mountains; along that to 44°30′ north; east to 34th meridian west from Washington>34° west from Washington; north to 45th parallel north	; then east.}} and the southeast third of Idaho Territory was transferred to Dakota Territory.{{efn>The new Dakota Territory–Idaho Territory border was, from the south: north along Washington meridians	to the crest of the Rocky Mountains, then northwest along that to the new tripoint with Montana Territory.}}Van Zandt, pp. 145–151{{usstat>13|85}}	alt=Map of the change to the United States in central North America on May 26, 1864|250px)

!scope=row|October 15, 1864

Malden Island was claimed by the United Kingdom of Great Britain and Ireland>United Kingdom.	Pacific Ocean:(File:United States Pacific change 1864-10-15.png	250px)

!scope=row|October 31, 1864

Nevada Territory was admitted as the thirty-sixth state, Nevada.{{usstat>13|749}}	alt=Map of the change to the United States in central North America on October 31, 1864|250px)

!scope=row|May 5, 1865

Confederate States of America>Confederate States cabinet met in Washington, Georgia, and dissolved.HTTP://WWW.CIVILWARONTHEWESTERNBORDER.ORG/TIMELINE/REMAINING-CONFEDERATE-CABINENT-DISSOLVES >TITLE=REMAINING CONFEDERATE CABINET DISSOLVES	ACCESS-DATE=MAY 21, 2015	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160303215240/HTTP://WWW.CIVILWARONTHEWESTERNBORDER.ORG/TIMELINE/REMAINING-CONFEDERATE-CABINENT-DISSOLVES, March 3, 2016, Military surrenders were scattered throughout 1865, but the most important is regarded as that of the Army of Northern Virginia following the Battle of Appomattox Court House on April 9.	Disputes:(File:United States Central dispute change 1865-05-05.png	250px)

“>

1866–1897 (Reconstruction and western statehood){|class“wikitable plainrowheaders”

!scope=“col“|Date!scope=“col“|Event!scope=“col“|Change Map!scope=row|May 5, 1866

Utah Territory west of 37th meridian west from Washington>37° west from Washington was transferred to Nevada.{{usstat	43}}	alt=Map of the change to the United States in central North America on May 5, 1866|250px)

!scope=row|July 24, 1866

Tennessee was readmitted to Congress.{{usstat>14|364}}	alt=Map of the change to the United States in central North America on July 24, 1866|250px)

!scope=row|December 26, 1866

Starbuck Island was claimed by the United Kingdom of Great Britain and Ireland>United Kingdom.	Pacific Ocean:(File:United States Pacific change 1866-12-26.png	250px)

!scope=row|January 18, 1867

Arizona Territory, west of the Colorado River and 37th meridian west from Washington>37° west from Washington, was transferred to Nevada. The law transferring the land was approved May 5, 1866, but unlike the Utah Territory transfer of that day, this transfer was contingent on the state accepting it.FIRST BIENNIAL REPORT OF THE NEVADA HISTORICAL SOCIETY >DATE=1909	PAGE=133	LAST1=SOCIETY	URL-STATUS=LIVE	ARCHIVE-DATE=APRIL 18, 2016,	alt=Map of the change to the United States in central North America on January 18, 1867|250px)

!scope=row|March 1, 1867

Nebraska Territory was admitted as the thirty-seventh state, Nebraska.{{usstat>14|820}}	alt=Map of the change to the United States in central North America on March 1, 1867|250px)

!scope=row|July 1, 1867|Canada was formed from several British colonies, including New Brunswick, thus inheriting the dispute over Machias Seal Island and North Rock.

Disputes:(File:United States Central dispute change 1867-07-01.png	250px)

!scope=row|August 28, 1867

Midway Atoll was claimed. An attempt had been made at the time of its discovery in 1859 to claim it under the Guano Islands Act.HAWAII. DEPT. OF THE ATTORNEY GENERAL	PUBLISHER=PARADISE OF THE PACIFIC PRESS	PAGE=244,books.google.com/books?id=0kwwAQAAMAAJ&pg=PA244,	Pacific Ocean:(File:United States Pacific change 1867-08-28.png	250px)

!scope=row|October 18, 1867

Russian Alaska>Alaska was Alaska Purchase	from the Russian Empire and designated the Department of Alaska.{{efn>The borders of the Department of Alaska were, from the Dixon Entrance: Up the Portland Canal	to 56th parallel north>56° north; then along the “summit of the mountains situated parallel to the coast” (the definition of which was disputed) to 141° west; then north.}}Van Zandt, pp. 165–166WEB ,avalon.law.yale.edu/19th_century/treatywi.asp , Treaty concerning the Cession of the Russian Possessions in North America by his Majesty the Emperor of all the Russias to the United States of America , The Avalon Project at Yale Law School , August 4, 2006 , live ,avalon.law.yale.edu/19th_century/treatywi.asp" title="web.archive.org/web/20090129101148avalon.law.yale.edu/19th_century/treatywi.asp">web.archive.org/web/20090129101148avalon.law.yale.edu/19th_century/treatywi.asp , January 29, 2009 , A vague description and lack of quality surveying made the southeastern border with British holdings unclear and disputed.	Northwestern North America:(File:United States Northwest change 1867-10-18.png	250px)

!scope=row|June 22, 1868

Arkansas was readmitted to Congress.{{usstat>15|72}}	alt=Map of the change to the United States in central North America on June 22, 1868|250px)

!scope=row|June 25, 1868

Florida was readmitted to Congress.Act authorizing readmission on ratification of 14th amendment: {{usstat>15|73}}. Florida ratified the amendment before that law was passed, so Florida was readmitted upon passage of the law.	alt=Map of the change to the United States in central North America on June 25, 1868|250px)

!scope=row|July 4, 1868

North Carolina was readmitted to Congress.Act authorizing readmission on ratification of 14th amendment: {{usstat>15	15|703}}.	alt=Map of the change to the United States in central North America on July 4, 1868|250px)

!scope=row|July 9, 1868

Louisiana and South Carolina were readmitted to Congress.Act authorizing readmission on ratification of 14th amendment: {{usstat>15	15|704}}.Caroline Island was claimed by the United Kingdom.	(File:United States Central change 1868-07-09.png	250px)Pacific Ocean:(File:United States Pacific change 1868-07-09.png	250px)

!scope=row|July 13, 1868

Alabama was readmitted to Congress.Act authorizing readmission on ratification of 14th amendment: {{usstat>15	15|704}}.	alt=Map of the change to the United States in central North America on July 13, 1868|250px)

!scope=row|July 25, 1868

Georgia (U.S. state)>Georgia was readmitted to Congress.HTTPS://BOOKS.GOOGLE.COM/BOOKS?ID=LWMI1XOKV7AC&PG=PA172 >TITLE=THE EMPIRE STATE OF THE SOUTH	ISBN=978-0-88146-111-4	YEAR=2008	URL-STATUS=LIVE	ARCHIVE-DATE=MAY 21, 2016, Wyoming Territory was organized from portions of Dakota, Idaho, and Utah Territories.{{efn|The borders of Wyoming Territory were parallels 41° north and 45° north, and Washington meridians 27° west and 34° west.}}{{usstat|15|178}}Van Zandt, pp. 144–145 The territory would remain under the jurisdiction of the Dakota Territory until its own government was organized on May 19, 1869.WEB,www.wyo.gov/about-wyoming/wyoming-history, Wyoming History, State of Wyoming, November 12, 2015, live,www.wyo.gov/about-wyoming/wyoming-history," title="web.archive.org/web/20151108111846www.wyo.gov/about-wyoming/wyoming-history,">web.archive.org/web/20151108111846www.wyo.gov/about-wyoming/wyoming-history, November 8, 2015, The act organizing Wyoming Territory became law on this date, but it is unclear if the territory could be considered “organized” until May 19, 1869, as the act specifies it was not to take effect until a government is organized; however, all sources use this date as the creation, and most use it for the organization, of the territory. A tiny portion of the Dakota Territory was erroneously left behind on the western side of Wyoming Territory.	alt=Map of the change to the United States in central North America on July 25, 1868|250px)

!scope=row|August 12, 1868

Guano Islands Act>guano island claims mentions “Islands in Caribbean Sea not named” bonded on this date, but it is unknown to what this is referring.	no change to map

!scope=row|December 11, 1868|Serrana Bank was claimed under the Guano Islands Act. Colombia has claimed it throughout its history.

Caribbean Sea:(File:United States Caribbean change 1868-12-11.png	250px)

!scope=row|March 3, 1869

Georgia (U.S. state)>Georgia was again expelled from Congress following failures of Reconstruction era	in the state.GEORGIA (UNITED STATES)	PAGES = 751–758; SEE PAGE 757,	alt=Map of the change to the United States in central North America on March 3, 1869|250px)

!scope=row|November 22, 1869

Bajo Nuevo Bank, Pedro Cays, Quita Sueño Bank, and Roncador Bank were claimed under the Guano Islands Act.JOHN BASSETT	PUBLISHER=U.S. GOVERNMENT PRINTING OFFICE	TITLE=A DIGEST OF INTERNATIONAL LAW AS EMBODIED IN DIPLOMATIC DISCUSSIONS, TREATIES AND OTHER INTERNATIONAL AGREEMENTS, INTERNATIONAL AWARDS, THE DECISIONS OF MUNICIPAL COURTS, AND THE WRITINGS OF JURISTS AND ESPECIALLY IN DOCUMENTS, PUBLISHED AND UNPUBLISHED, ISSUED BY PRESIDENTS AND SECRETARIES OF STATE OF THE UNITED STATES, THE OPINIONS OF THE ATTORNEYS-GENERAL, AND THE DECISIONS OF COURTS, FEDERAL AND STATE	URL=HTTPS://BOOKS.GOOGLE.COM/BOOKS?ID=9MIHAQAAIAAJ&Q=MORANT%20KEYS%20GUANO%20CLAIM%20BRITISH&PG=PA566	URL-STATUS=LIVE	ARCHIVE-DATE=MAY 1, 2016, HTTPS://WWW.DOI.GOV/OIA/ISLANDS/ACQUISITIONPROCESS >TITLE=ACQUISITION PROCESS OF INSULAR AREAS	PUBLISHER=UNITED STATES DEPARTMENT OF THE INTERIOR OFFICE OF INSULAR AFFAIRS	URL-STATUS=LIVE	ARCHIVE-DATE=AUGUST 15, 2016, Except for Pedro Cays, Colombia has claimed them throughout its history.	Caribbean Sea:(File:United States Caribbean change 1869-11-22.png	250px)

!scope=row|January 26, 1870

Virginia was readmitted to Congress.{{usstat>16|62}}	alt=Map of the change to the United States in central North America on January 26, 1870|250px)

!scope=row|February 23, 1870

Mississippi was readmitted to Congress.{{usstat>16|67}}	alt=Map of the change to the United States in central North America on February 23, 1870|250px)

!scope=row|March 30, 1870

Texas was readmitted to Congress.{{usstat>16|80}}	alt=Map of the change to the United States in central North America on March 30, 1870|250px)

!scope=row|July 15, 1870

Georgia (U.S. state)>Georgia was again readmitted to Congress.{{usstat	363}}The North-Western Territory was transferred by the United Kingdom to Canada, thus transferring its portion of the Alaska boundary dispute.ENCYCLOPEDIA,www.thecanadianencyclopedia.ca/en/article/northwest-territories/, Northwest Territories, The Canadian Encyclopedia, July 6, 2015, live,www.thecanadianencyclopedia.ca/en/article/northwest-territories/," title="web.archive.org/web/20150627110823www.thecanadianencyclopedia.ca/en/article/northwest-territories/,">web.archive.org/web/20150627110823www.thecanadianencyclopedia.ca/en/article/northwest-territories/, June 27, 2015,	(File:United States Central change 1870-07-15.png	250px)Northwestern North America:(File:United States Northwest change 1870-07-15.png	250px)

!scope=row|February 9, 1871

Dakota Territory to Nebraska following a sudden change in course of the Missouri River.{{usstat>16|93}}	alt=Map of the change to the United States in central North America on February 9, 1871|250px)

!scope=row|July 20, 1871

British Columbia joined Canada, transferring the Pig War (1859)>dispute over the San Juan Islands as well as its portion of the Alaska boundary dispute.HTTP://WWW.THECANADIANENCYCLOPEDIA.CA/EN/ARTICLE/BRITISH-COLUMBIA/ >TITLE=BRITISH COLUMBIA	ACCESS-DATE=JULY 6, 2015	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20150620093319/HTTP://WWW.THECANADIANENCYCLOPEDIA.CA/EN/ARTICLE/BRITISH-COLUMBIA/, June 20, 2015,	Disputes:(File:United States Central dispute change 1871-07-20.png	250px)Northwestern North America:(File:United States Northwest change 1871-07-20.png	250px)

!scope=row|October 21, 1872

Pig War (1859)>dispute with Canada over the San Juan Islands was resolved in the favor of the United States claim.Van Zandt, p. 18	Disputes:(File:United States Central dispute change 1872-10-21.png	250px)

!scope=row|1873

Vostok Island was claimed by the United Kingdom of Great Britain and Ireland>United Kingdom.VOSTOK ISLAND >ENCYCLOPEDIA=HISTORICAL DICTIONARY OF THE BRITISH EMPIRE	PUBLISHER=ROWMAN & LITTLEFIELD	LONDON >PAGES=561–562	ACCESS-DATE=JULY 2, 2015	URL-STATUS=LIVE	ARCHIVE-DATE=MAY 16, 2016,	Pacific Ocean:(File:United States Pacific change 1873-00-00.png	250px)

!scope=row|February 17, 1873

Lost Dakota>small portion of Dakota Territory that was left behind when Wyoming Territory was created was transferred to Montana Territory.Van Zandt, pp. 136, 149–150{{usstat	464}}	alt=Map of the change to the United States in Central North America on February 17, 1873|250px)

!scope=row|August 1, 1876

Colorado Territory was admitted as the thirty-eighth state, Colorado.{{usstat>18|474}}	alt=Map of the change to the United States in central North America on August 1, 1876|250px)

!scope=row|August 13, 1877

United Kingdom of Great Britain and Ireland>United Kingdom created the British Western Pacific Territories, including Atafu and Nukunono.UNION ISLANDS >ENCYCLOPEDIA=HISTORICAL DICTIONARY OF THE BRITISH EMPIRE	PUBLISHER=ROWMAN & LITTLEFIELD	LONDON >PAGES=540–541	ACCESS-DATE=JULY 2, 2015	URL-STATUS=LIVE	ARCHIVE-DATE=MAY 6, 2016,	Pacific Ocean:(File:United States Pacific change 1877-08-13.png	250px)

!scope=row|March 3, 1879|The border across the Chesapeake Bay between Maryland and Virginia was decided via arbitration. It is unknown if any land actually changed hands.

too vague to map

!scope=row|September 8, 1879|Arenas Key, claimed by Mexico; the Morant Cays; and Serranilla Bank, claimed by Colombia, were claimed by the United States under the Guano Islands Act; according to the Office of Insular Affairs, Serranilla Bank was claimed again on September 13, 1880.

Caribbean Sea:(File:United States Caribbean change 1879-09-08.png	250px)

!scope=row|April 7, 1880

Fair Haven, Vermont, was transferred to New York (state)>New York in response to a change in the course in the Poultney River.{{usstat	72}}	too small to map

!scope=row|September 13, 1880

Western Triangle Island, claimed by Mexico, was claimed by the United States under the Guano Islands Act. The list of bonded claims also mentions a “De Anes” island claimed on this date, with coordinates matching Isla Aves>Isla de Aves; however, the same list points out that the claim to “Aves Island” was found to be invalid.	Caribbean Sea:(File:United States Caribbean change 1880-09-13.png	250px)

!scope=row|1881

Flint Island was claimed by the United Kingdom of Great Britain and Ireland>United Kingdom.FLINT ISLAND >ENCYCLOPEDIA=HISTORICAL DICTIONARY OF THE BRITISH EMPIRE	PUBLISHER=ROWMAN & LITTLEFIELD	LONDON >PAGE=191	ACCESS-DATE=JULY 2, 2015	URL-STATUS=LIVE	ARCHIVE-DATE=MAY 12, 2016,	Pacific Ocean:(File:United States Pacific change 1881-00-00.png	250px)

!scope=row|May 23, 1882

43rd parallel north>43° north and the Keya Paha River	and Niobrara River>Niobrara Rivers was transferred from Dakota Territory to Nebraska.{{usstat	35}} The act was passed in Congress on March 28 and accepted by the Nebraska legislature on this date.JOURNAL, Watkins, Albert, 1913, Nebraska Territorial Acquisition,books.google.com/books?id=j0lHAQAAMAAJ&pg=PA53, Collections of the Nebraska State Historical Society, Nebraska State Historical Society, XVII, 53, May 18, 2015,	alt=Map of the change to the United States in central North America on May 23, 1882|250px)

!scope=row|June 1, 1882

Morant Cays and Pedro Cays were annexed by the United Kingdom of Great Britain and Ireland>United Kingdom to Jamaica; it appears they were no longer claimed by the United States after this.Letters Patent ... for the Annexation of Morant and Pedro Cays to the Island of Jamaica {{webarchive	books.google.com/books?id=wEIBAAAAYAAJ&pg=PA1601&hl=en&sa=X&ei=dLGHVf3HKIutyQSM3IKAAQ&ved=0CCwQ6AEwAQ >date=April 17, 2016 }}	Caribbean Sea:(File:United States Caribbean change 1882-06-01.png	250px)

!scope=row|May 17, 1884

Department of Alaska was organized into the District of Alaska.{{usstat>23|24}}	Northwestern North America:(File:United States Northwest change 1884-05-17.png	250px)

!scope=row|June 21, 1884

Scorpion Reef>Alacrans Islands, claimed by Mexico, were claimed under the Guano Islands Act.	Caribbean Sea:(File:United States Caribbean change 1884-06-21.png	250px)

!scope=row|March 15, 1888

Tabuaeran>Fanning Island was annexed by the United Kingdom; it appears the island was no longer claimed by the United States after this.	Pacific Ocean:(File:United States Pacific change 1888-03-15.png	250px)

!scope=row|March 17, 1888

Kiritimati>Christmas Island was claimed by the United Kingdom.	Pacific Ocean:(File:United States Pacific change 1888-03-17.png	250px)

!scope=row|October 26, 1888

Cook Islands became a protectorate of the United Kingdom of Great Britain and Ireland>United Kingdom, thus initiating a claim on the atolls of Manihiki, Penrhyn (atoll)	, Pukapuka, and Rakahanga.CHRONOLOGY	YEAR=2015	LOCATION=LONDON	URL=HTTPS://BOOKS.GOOGLE.COM/BOOKS?ID=WDFBCQAAQBAJ&PG=PR19	ISBN=978-0-8108-7524-1	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160408060413/HTTPS://BOOKS.GOOGLE.COM/BOOKS?ID=WDFBCQAAQBAJ&LPG=PP1&PG=PR19, April 8, 2016,	Pacific Ocean:(File:United States Pacific change 1888-10-26.png	250px)

!scope=row|May 29, 1889

Teraina>Washington Island was annexed by the United Kingdom; it appears the island was no longer claimed by the United States after this.JOURNAL, 1914,books.google.com/books?id=lbgjAQAAIAAJ&q=march+15+1888, United Empire, Unknown title, Royal Colonial Institute, 4, 266, June 22, 2015,	Pacific Ocean:(File:United States Pacific change 1889-05-29.png	250px)

!scope=row|June 3, 1889

Jarvis Island was claimed by the United Kingdom of Great Britain and Ireland>United Kingdom.	Pacific Ocean:(File:United States Pacific change 1889-06-03.png	250px)

!scope=row|June 26, 1889

Manra Island>Sydney Island was claimed by the United Kingdom.	Pacific Ocean:(File:United States Pacific change 1889-06-26.png	250px)

!scope=row|June 29, 1889

Rawaki Island>Phoenix Island was claimed by the United Kingdom.	Pacific Ocean:(File:United States Pacific change 1889-06-29.png	250px)

!scope=row|July 10, 1889

Birnie Island was claimed by the United Kingdom of Great Britain and Ireland>United Kingdom.	Pacific Ocean:(File:United States Pacific change 1889-07-10.png	250px)

!scope=row|November 2, 1889

Dakota Territory was split in half along the “seventh standard parallel north”, a few miles south of 46th parallel north>46° north, and admitted as the thirty-ninth state, North Dakota, and the fortieth state, South Dakota.	alt=Map of the change to the United States in central North America on November 2, 1889|250px)

!scope=row|November 8, 1889|Montana Territory was admitted as the forty-first state, Montana.

alt=Map of the change to the United States in central North America on November 8, 1889|250px)

!scope=row|November 11, 1889

Washington Territory was admitted as the forty-second state, Washington (state)>Washington.{{usstat	676}}	alt=Map of the change to the United States in central North America on November 11, 1889|250px)

!scope=row|May 2, 1890

Oklahoma Territory was Oklahoma Organic Act>organized from the Public Land Strip and the western half of Indian Territory, except for the Cherokee Outlet, which would be added later upon cession from the Cherokee.{{efn	Red River of the South>Red River meets 98th meridian west	: north to the Canadian River; down that to Seminole land; north along that border to the North Canadian River; down that to Creek people>Creek land; north and east along that border to 96th meridian west	; then north. This omits the Cherokee Outlet, whose complex borders separated the main portion of Oklahoma Territory from the former Public Land Strip.}}{{usstat>26|81}}Van Zandt, pp. 139–140	alt=Map of the change to the United States in central North America on May 2, 1890|250px)

!scope=row|July 3, 1890

Idaho Territory was admitted as the forty-third state, Idaho.{{usstat>26|215}}	alt=Map of the change to the United States in central North America on July 3, 1890|250px)

!scope=row|July 10, 1890

Wyoming Territory was admitted as the forty-fourth state, Wyoming.{{usstat>26|222}}	alt=Map of the change to the United States in central North America on July 10, 1890|250px)

!scope=row|March 8, 1892

Gilbert Islands became a protectorate of the United Kingdom of Great Britain and Ireland>United Kingdom, thus initiating a claim on Butaritari and Marakei. No record of a United States claim exists after this point, so it is assumed this is when the claim fell dormant.	Pacific Ocean:(File:United States Pacific change 1892-03-08.png	250px)

!scope=row|May 28, 1892

Nikumaroro>Gardner Island was claimed by the United Kingdom.	Pacific Ocean:(File:United States Pacific change 1892-05-28.png	250px)

!scope=row|September 16, 1893

Cherokee, the federal government purchased the Cherokee Outlet in the Indian Territory and opened it to settlement, transferring it to Oklahoma Territory as provided in the Oklahoma Organic Act.{{usstat>27|640}}	alt=Map of the change to the United States in central North America on September 16, 1893|250px)

!scope=row|November 17, 1894

Scorpion Reef>Alacrans Islands, Arenas Key, and Western Triangle Island were stricken from the list of claimed guano islands.	Caribbean Sea:(File:United States Caribbean change 1894-11-17.png	250px)

!scope=row|January 4, 1896

Utah Territory was admitted as the forty-fifth state, Utah.{{usstat>28|107}}	alt=Map of the change to the United States in central North America on January 4, 1896|250px)

!scope=row|March 16, 1896

Oklahoma Territory, and Texas over Greer County, Texas>Greer County was resolved in favor of the federal claim.{{ussc	1|1896}}	alt=Map of the change to the United States in central North America on March 16, 1896|250px)

!scope=row|July 24, 1897

Missouri River, an island was transferred from Nebraska to South Dakota.{{usstat>30|214}}	alt=Map of the change to the United States in central North America on July 24, 1897|250px)

“>

1898–1945 (Pacific and Caribbean expansion){|class“wikitable plainrowheaders”

!scope=“col“|Date!scope=“col“|Event!scope=“col“|Change Map!scope=row|August 12, 1898

Republic of Hawaii was annexed.HTTPS://HISTORY.STATE.GOV/COUNTRIES/HAWAII	PUBLISHER=OFFICE OF THE HISTORIAN, BUREAU OF PUBLIC AFFAIRS, UNITED STATES DEPARTMENT OF STATE	URL-STATUS=LIVE	ARCHIVE-DATE=JUNE 19, 2015, The ceremony to transfer sovereignty occurred on this date; the Newlands Resolution	was signed on July 7, 1898.{{USStat>30	Johnston Atoll was not included with Hawaii, nor was Sikaiana>Sikaiana Atoll, which had been ceded to Hawaii in 1856 by its residents and approved by King Kamehameha IV. However, the annexation was based on the islands named in a report of the Hawaiian Commission, which omitted Sikaiana.“U.S. Insular Areas: Application of the U.S. Constitution” {{webarchive	www.gao.gov/archive/1998/og98005.pdf >date=February 16, 2008 }} (pdf). Report to the Chairman, Committee on Resources, House of Representatives. United States General Accounting Office. November 1997. Page 39, footnote 2.Report of the Hawaiian Commission, S. Doc. No. 16, 55th Cong., at 4 (3d Sess. 1898)	Pacific Ocean:(File:United States Pacific change 1898-08-12.png	250px)

!scope=row|January 17, 1899

Wake Island was claimed.HTTPS://TIMESMACHINE.NYTIMES.COM/TIMESMACHINE/1899/03/22/117916635.PDF	NEWSPAPER=THE NEW YORK TIMES	ACCESS-DATE=MAY 14, 2015, {{dead link	bot=medic}}{{cbignore|bot=medic}}	Pacific Ocean:(File:United States Pacific change 1899-01-17.png	250px)

!scope=row|April 11, 1899

Guam, Puerto Rico>Porto Rico, and, on agreed payment of $20 million, the Philippines were Treaty of Paris (1898)	by Spain following the Spanish–American War.HTTP://AVALON.LAW.YALE.EDU/19TH_CENTURY/SP1898.ASP	PUBLISHER=THE AVALON PROJECT AT YALE LAW SCHOOL	URL-STATUS=LIVE	ARCHIVE-DATE=MAY 23, 2015, The Philippines were claimed by the First Philippine Republic. The ceded region for the Philippines included the island of Palmas, which was administered by the Netherlands. This overlap would not be noticed until January 21, 1906. While the United States occupied Cuba for a time, it was not ceded nor claimed.	Pacific Ocean:(File:United States Pacific change 1899-04-11.png	250px)Caribbean Sea:(File:United States Caribbean change 1899-04-11.png	250px)

!scope=row|February 16, 1900|The United States took ownership of the Samoan Islands east of 171° west, per the terms of the Tripartite Convention.

Pacific Ocean:(File:United States Pacific change 1900-02-16.png	250px)

!scope=row|February 19, 1900

American Samoa>Naval Station, Tutuila. It included all of the islands granted by the Tripartite Convention, though formal cession of the islands by local authorities would take place later in 1900 and 1904.	Pacific Ocean:(File:United States Pacific change 1900-02-19.png	250px)

!scope=row|April 12, 1900

Puerto Rico>Porto Rico was Foraker Act	into a civil territory.{{USStat>31|77}}	no change to map

!scope=row|April 17, 1900

Tutuila was Treaty of Cession of Tutuila>formally ceded to the United States and added to American Samoa	.HTTP://WWW.ASBAR.ORG/ARCHIVE/NEWCODE/TREATIES.HTM	PUBLISHER=AMERICAN SAMOA BAR ASSOCIATION	URL-STATUS=LIVE	ARCHIVE-DATE=MARCH 4, 2016,americansamoa.noaa.gov/about/history.html National Marine Sanctuary of American Samoa. History. americansamoa.noaa.gov. Retrieved January 18, 2018. As the United States had already claimed the island on February 19, 1900, no change is mapped. The treaty would be ratified by Congress on February 20, 1929.	no change to map

!scope=row|June 14, 1900

Republic of Hawaii was Hawaiian Organic Act>organized into Hawaii Territory.{{USStat	141}}Van Zandt, p. 166	Pacific Ocean:(File:United States Pacific change 1900-06-14.png	250px)

!scope=row|March 3, 1901

Bristol, Tennessee, to Bristol, Virginia, was approved by Congress after having been approved by both states.{{usstat>31	Virginia Compacts – Boundary with Tennessee {{webarchive>url=https://web.archive.org/web/20160624063947law.lis.virginia.gov/compacts/boundary-with-tennessee/ |date=June 24, 2016 }} The location of the border along Main Street (now State Street) between the two cities was either the northern sidewalk of the street, or down the middle of the street; Tennessee’s cession of the northern half of the street laid the issue to rest.	too small to map

!scope=row|March 23, 1901|The president of the First Philippine Republic, Emilio Aguinaldo, was captured, and the republic was dissolved.On this same date several islands, Cagayan de Sulu and Sibutu among them, were purchased from Spain and assigned to the Philippines, which was then being governed as a U.S. insular area. The borders specified in the Treaty of Paris of 1898 had excluded these islands; the new treaty simply ceded “any and all islands belonging to the Philippine Archipelago”.Map of the borders of the Treaty of Paris (1898){{usstat|31|1942}}

Pacific Ocean:(File:United States Pacific change 1901-03-23.png	250px)

!scope=row|July 4, 1901

Insular Government of the Philippine Islands was established.HTTPS://HISTORY.HOUSE.GOV/EXHIBITIONS-AND-PUBLICATIONS/APA/HISTORICAL-ESSAYS/EXCLUSION-AND-EMPIRE/THE-PHILIPPINES/	PUBLISHER=OFFICE OF THE HISTORIAN OF THE UNITED STATES HOUSE OF REPRESENTATIVES	31|895}}	Pacific Ocean:(File:United States Pacific change 1901-07-04.png	250px)

!scope=row|July 1, 1902

Insular Government of the Philippine Islands>Philippines were Philippine Organic Act (1902)	.{{usstat>32|691}}	no change to map

!scope=row|October 20, 1903|The Alaska boundary dispute with Canada was resolved, generally in favor of the United States claim.Van Zandt, pp. 29–33

Northwestern North America:(File:United States Northwest change 1903-10-20.png	250px)

!scope=row|December 10, 1903

Guantánamo Bay was Cuban–American Treaty of Relations (1903)>leased in perpetuity from Cuba for use as a naval base;WEB ,avalon.law.yale.edu/20th_century/dip_cuba002.asp , Agreement Between the United States and Cuba for the Lease of Lands for Coaling and Naval stations; February 23, 1903 , The Avalon Project at Yale Law School , June 13, 2016 , live ,avalon.law.yale.edu/20th_century/dip_cuba002.asp" title="web.archive.org/web/20160604195511avalon.law.yale.edu/20th_century/dip_cuba002.asp">web.archive.org/web/20160604195511avalon.law.yale.edu/20th_century/dip_cuba002.asp , June 4, 2016 , the treaty took effect February 23, 1903, and the formal handover occurred on this date.MAGAZINE,www.newyorker.com/news/news-desk/a-useful-corner-of-the-world-guantnamo, A Useful Corner of the World: Guantánamo, The New Yorker, July 30, 2013, Kramer, Paul, June 4, 2018,

no change to map

!scope=row|May 4, 1904

Panama Canal Zone. At this stage, only the most basic borders were defined; it was a zone surrounding the canal on each side for five miles, but excluded the cities of Colón, Panama>Colón and Panama City, which remained exclaves of Panama, as well as the water for their harbors.HTTPS://BOOKS.GOOGLE.COM/BOOKS?ID=AYAAAAAAIAAJ&PG=PA133 >TITLE=AND THE MOUNTAINS WILL MOVE: THE STORY OF THE BUILDING OF THE PANAMA CANAL	YEAR=1947	STANFORD UNIVERSITY PRESS >ACCESS-DATE=MAY 12, 2015	URL-STATUS=LIVE	ARCHIVE-DATE=APRIL 24, 2016, The Hay–Bunau-Varilla Treaty granting it to the United States was ratified on February 26, 1904.{{USStat	2234}} A formal border agreement, which also gave the Canal Zone some land and a lighthouse in northwest Colón, would be ratified on June 15, 1904.Canal Zone Boundaries {{webarchive	books.google.com/books?id=0UQ6AQAAIAAJ&lpg=PA678&ots=1Nl1z4L2jk&pg=PA678 >date=April 28, 2016 }}; signed June 15, 1904; accessed June 30, 2015	Caribbean Sea:(File:United States Caribbean change 1904-05-04.png	250px)

!scope=row|July 16, 1904

Manuʻa islands were Treaty of Cession of Manuʻa>formally ceded to the United States and added to American Samoa	. As the United States had already claimed the islands on February 19, 1900, no change is mapped. The Ratification Act of 1929>treaty would be ratified by Congress on February 20, 1929.	no change to map

!scope=row|December 12, 1904

Panama on December 3, with one of its sections refining the maritime boundary of the harbor of Panama City and the Panama Canal Zone.HEARINGS CONCERNING ESTIMATES FOR CONSTRUCTION OF THE ISTHMIAN CANAL FOR THE FISCAL YEAR 1909	URL=HTTPS://ARCHIVE.ORG/DETAILS/HEARINGSCONCERN01TAWNGOOG	396 > ACCESS-DATE=JULY 6, 2015	FIRST1=UNITED STATES. CONGRESS. HOUSE	FIRST2=JAMES A, 1908, H.R. Doc. No. 458 part 10, 58th Cong., 2nd Sess. (1904), pp. 936–941 (Specifically for this citation, sec. 5 on page 938) It became effective December 12.	no change to map

!scope=row|February 10, 1905

Arkansas and Indian Territory was slightly adjusted near Fort Smith, Arkansas, transferring a small amount of land on the east side of the Poteau River to Arkansas.{{usstat>33|714}}JOURNAL , Myers , Arther J. , Vosburg , David L. , November 1964 , Distances Within the State of Oklahoma ,www.ogs.ou.edu/pubsscanned/NOTES/GN-V24N11.pdf , Oklahoma Geology Notes , University of Oklahoma , 24 , 11 , 256 , May 17, 2015 , live ,www.ogs.ou.edu/pubsscanned/NOTES/GN-V24N11.pdf" title="web.archive.org/web/20160304192330www.ogs.ou.edu/pubsscanned/NOTES/GN-V24N11.pdf">web.archive.org/web/20160304192330www.ogs.ou.edu/pubsscanned/NOTES/GN-V24N11.pdf , March 4, 2016 ,

alt=Map of the change to the United States in central North America on February 10, 1905|250px)

!scope=row|September 26, 1907

New Zealand became largely Independence of New Zealand>independent from the United Kingdom of Great Britain and Ireland	,Proclamation, dated September 9, 1907, declaring that the Colony of New Zealand shall be called and known by the title of the Dominion of New Zealand inheriting the claim on the atolls of Manihiki, Penrhyn (atoll)>Penrhyn, Pukapuka, and Rakahanga.	Pacific Ocean:(File:United States Pacific change 1907-09-26.png	250px)

!scope=row|November 16, 1907

Indian Territory and Oklahoma Territory were combined and admitted as the forty-sixth state, Oklahoma.{{USStat>35|2160}}	alt=Map of the change to the United States in central North America on November 16, 1907|250px)

!scope=row|April 11, 1908

United Kingdom of Great Britain and Ireland>United Kingdom on behalf of Canada redefined the maritime borders between the United States and Canada.Van Zandt, pp. 18–20 Among other changes, this “de-enclaved” Horseshoe Reef Lighthouse in Lake Erie by making the water around it contiguous with the water on the American side of the border.HTTPS://WWW.SCRIBD.COM/DOC/282773953/STLAWRENCERIVER-GREATLAKES-12 >TITLE=INTERNATIONAL BOUNDARY BETWEEN THE UNITED STATES AND THE DOMINION OF CANADA THROUGH THE ST. LAWRENCE RIVER AND GREAT LAKES, SHEET NO. 12 – NIAGARA RIVER	DATE=AUGUST 15, 1913	LOCATION=BUFFALO, NEW YORK	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160304064348/HTTPS://WWW.SCRIBD.COM/DOC/282773953/STLAWRENCERIVER-GREATLAKES-12, March 4, 2016,	no change to map

!scope=row|January 1, 1909|The new Constitution of Michigan included some area of Wisconsin within its definition of Michigan.

alt=Map of the change to the United States in central North America on January 1, 1909|250px)

!scope=row|August 20, 1910

United Kingdom of Great Britain and Ireland>United Kingdom on behalf of Canada addressed a slight uncertainty in the maritime border in Passamaquoddy Bay between Maine and Canada.36 Stat. 2477Van Zandt, p. 20HTTPS://2009-2017.STATE.GOV/E/OES/OCNS/OPA/C28187.HTM > TITLE=MARITIME BOUNDARIES	ACCESS-DATE=AUGUST 19, 2018, The border was adjusted to run east of Pope’s Folly Island, which previously lay on the border line, and had been the subject of some debate for many years.HTTPS://WWW.NYTIMES.COM/1893/06/20/ARCHIVES/WHO-OWNS-POPES-FOLLY-ISLAND-GREAT-BRITAINS-ORIGINAL-CHART-CONCEDED.HTML >TITLE=WHO OWNS POPE’S FOLLY ISLAND?	THE NEW YORK TIMES >DATE=JUNE 20, 1893	URL-STATUS=LIVE	ARCHIVE-DATE=MARCH 5, 2016, Link to a download for the United States Geological Survey map of the Eastport Quadrangle from 1907: ims.er.usgs.gov/gda_services/download?item_id=5637963" title="https:/-/web.archive.org/web/20170803135014ims.er.usgs.gov/gda_services/download?item_id=5637963">weblink	alt=Map of the change to the United States in central North America on August 20, 1910|250px)

!scope=row|July 17, 1911

American Samoa;HTTP://WWW.SAMOANEWS.COM/VIEWSTORY.PHP?STORYID=7779	ARCHIVE-DATE=SEPTEMBER 27, 2011	DATE=JULY 16, 2009	PUBLISHER=SAMOA NEWS	United States Naval Station Tutuila>continued to operate separate from territorial governance until 1951.	Pacific Ocean:(File:United States Pacific change 1911-07-17.png	250px)

!scope=row|January 6, 1912

New Mexico Territory was admitted as the forty-seventh state, New Mexico.{{usstat>37|39}}	alt=Map of the change to the United States in central North America on January 6, 1912|250px)

!scope=row|February 14, 1912

Arizona Territory was admitted as the forty-eighth state, Arizona.{{usstat>37|1728}}	alt=Map of the change to the United States in central North America on February 14, 1912|250px)

!scope=row|August 24, 1912

District of Alaska was reorganized as the Alaska Territory.{{USStat>37|512}}	Northwestern North America:(File:United States Northwest change 1912-08-24.png	250px)

!scope=row|January 31, 1913

Supreme Court of the United States>Supreme Court against Texas over the “Country Club Dispute”, questioning whether the present course or the 1850 course of the Rio Grande should be their border.JOURNAL , Bowden , J.J. , October 1959 , The Texas-New Mexico Boundary Dispute Along the Rio Grande ,faculty.utep.edu/LinkClick.aspx?link=Bowden_NM-TX+boundary.pdf&tabid=72958&mid=166250 , Southwestern Historical Quarterly , Texas State Historical Association , 63 , 2 , 221–237 , May 11, 2015 ,faculty.utep.edu/LinkClick.aspx?link=Bowden_NM-TX+boundary.pdf&tabid=72958&mid=166250" title="web.archive.org/web/20160304035215faculty.utep.edu/LinkClick.aspx?link=Bowden_NM-TX+boundary.pdf&tabid=72958&mid=166250">web.archive.org/web/20160304035215faculty.utep.edu/LinkClick.aspx?link=Bowden_NM-TX+boundary.pdf&tabid=72958&mid=166250 , March 4, 2016 , dead ,

alt=Map of the change to the United States in central North America on January 31, 1913|250px)

!scope=row|August 5, 1914

Corn Islands were Bryan–Chamorro Treaty>leased from Nicaragua for a period of 99 years; however, this was not a full transfer of sovereignty, and the islands were never administered as an insular area.	no change to map

!scope=row|May 1, 1915

Panama Canal Zone were explicitly defined. Whereas the original definition was a simple corridor surrounding the canal, this treaty specified the actual border. Among the changes this caused were: a slice of Canal Zone was ceded to Panama so Panama City would be connected with the rest of the country; the middle island of the Las Tres Hermanas Islands, which marked the border of Panama City’s harbor, was wholly made part of Canal Zone; Gatun Lake and other surrounding waters were formally annexed to the territory; and an area of northwest Colón, Panama>Colón was ceded to Canal Zone.{{usstat	1893}}Canal Zone Boundaries {{webarchive	books.google.com/books?id=0UQ6AQAAIAAJ&ots=1Nl-C4G1ko&pg=PA702 >date=May 16, 2016 }}, signed September 2, 1914; U.S. Treaty Series 610; accessed June 30, 2015BOUNDARY CONVENTION >DATE=JUNE 9, 1915	LOCATION=BALBOA HEIGHTS, PANAMA	URL=HTTPS://WWW.NEWSPAPERS.COM/IMAGE/50612129	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160827105545/HTTP://WWW.NEWSPAPERS.COM/IMAGE/50612129/, August 27, 2016,	Caribbean Sea:(File:United States Caribbean change 1915-05-01.png	250px)

!scope=row|May 27, 1915

Hay–Bunau-Varilla Treaty>1903 Treaty, the United States expropriated from Panama several areas around the mouth of the Rio Chagres, annexing them to the Panama Canal Zone.THE UNITED STATES AND THE REPUBLIC OF PANAMA (2ND PRINTING) >FIRST=WILLIAM D.	LOCATION= NEW YORK	YEAR=1965, 144–159,	too small to map

!scope=row|December 8, 1915|The United States expropriated from Panama a triangle of land, which included the historic Fort San Lorenzo, between the Rio Chagres, Caribbean Sea and the Panama Canal Zone, to which it was annexed.

too small to map

!scope=row|January 17, 1916

Navassa Island was formally claimed for lighthouse purposes.{{usstat>39|1763}}	no change to map

!scope=row|August 29, 1916

Insular Government of the Philippine Islands>Philippines were Jones Law (Philippines)	to provide more autonomous government.{{usstat>39|545}}	no change to map

!scope=row|March 31, 1917

Danish Virgin Islands were Treaty of the Danish West Indies>purchased from Denmark{{USStat	1706}} and renamed the United States Virgin Islands.Van Zandt, pp. 39–40	Caribbean Sea:(File:United States Caribbean change 1917-03-31.png	250px)

!scope=row|July 12, 1918

Panama 2.6 hectares of land at Panama City#Neighborhoods>Punta Paitilla in Panama City and annexed it to the Panama Canal Zone.PANAMA>PUBLISHER=REPUBLIC OF PANAMA

PAGES=303–305

YEAR=1919

PAGES=584–585

NUMBER=39

DATE=MAY 12, 1920

QUOTE=... IT WAS NOT UNTIL THE YEAR 1918, WHEN THE GOVERNOR OF THE CANAL ZONE ADDRESSED A COMMUNICATION TO THE SECRETARY OF FOREIGN AFFAIRS OF THE REPUBLIC OF PANAMA STATING THAT THE UNITED STATES GOVERNMENT WOULD REQUIRE 50.6 HECTARES, THAT THE EXACT AREA EXPROPRIATED WAS DEFINITELY KNOWN., ANNUAL REPORT OF THE GOVERNOR OF THE PANAMA CANAL FOR THE FISCAL YEAR ENDED JUNE 30, 1919 >URL=HTTPS://ARCHIVE.ORG/DETAILS/ANNUALREPORTOFGO1919CANA

PUBLISHER=U.S. GOVERNMENT PRINTING OFFICE

LOCATION=WASHINGTON, DC

94 >QUOTE=A SURVEY WAS MADE AND A MAP DRAWN UP SHOWING THE BOUNDARY LINES OF THE PUNTA PAITILLA MILITARY RESERVATION. VARIOUS AREAS WERE DETERMINED WITH REFERENCE TO HIGH AND LOW WATER AND THE OLD AND NEW CITY BOUNDARY LINES. PERMANENT MONUMENTS WERE SET AND A DESCRIPTION WRITTEN UP BY METES AND BOUNDS. A TRACING WAS MADE OF THE MAP OF THE MILITARY RESERVATION KNOWN AS AREA ‘A’.

ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160506134624/HTTPS://ARCHIVE.ORG/DETAILS/ANNUALREPORTOFGO1919CANA

LOCATION=NATIONAL ARCHIVES, COLLEGE PARK, MARYLAND

DATE=1927

ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20161011034402/HTTPS://CATALOG.ARCHIVES.GOV/ID/6861831?Q=MAP%20PANAMA%20CANAL, October 11, 2016, (with hand-drawn features dated 1932)

too small to map

!scope=row|August 21, 1918|The United States expropriated from Panama land between the Rio Chagres and the Quebrada Majagual and annexed it to the Panama Canal Zone.

Caribbean Sea:(File:United States Caribbean change 1918-08-21.png	250px)

!scope=row|September 13, 1918

Minnesota and Wisconsin exchanged islands in the Mississippi River: Island Seventytwo was transferred to Winona, Minnesota, and Barron’s Island was transferred to La Crosse, Wisconsin.{{usstat>40|959}}	alt=Map of the change to the United States in central North America on September 13, 1918|250px)

!scope=row|September 18, 1919|The island of Largo Remo was annexed to the Panama Canal Zone under the United States right of expropriation in the 1903 Canal Treaty.U.S. For. Rel., 1920, III, 314–322; Specifically, page 315, D-No. 60

Caribbean Sea:(File:United States Caribbean change 1919-09-18.png	250px)

!scope=row|June 16, 1920|Fifteen hectares on the island of Taboga Island were annexed to the Panama Canal Zone.U.S. For. Rel., 1920, III, 314–322; Specifically, page 322, S.P.-No. 1362

too small to map

!scope=row|June 30, 1921

Wedge (border)>Wedge” dispute between Delaware and Pennsylvania was resolved in Delaware’s favor. The disputed land had generally been administered by Delaware, even electing a member of the Delaware legislature in the mid-19th century,WALKIN’ THE LINE: A JOURNEY FROM PAST TO PRESENT ALONG THE MASON-DIXON >AUTHOR=ECENBARGER, BILL	PUBLISHER=M. EVANS AND COMPANY, INC.	PAGES=89–91	ISBN=978-1-4617-1076-9	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160423134203/HTTPS://BOOKS.GOOGLE.COM/BOOKS?ID=6LFAGEUD5Z4C&LPG=PA91&PG=PA90	United States Geological Survey map of the Elkton Quadrangle from August 1900: ims.er.usgs.gov/gda_services/download?item_id=5368074" title="https:/-/web.archive.org/web/20170908064726ims.er.usgs.gov/gda_services/download?item_id=5368074">weblink. Note that later reprints of the same map, as early as 1906, changed ownership of the Wedge to Delaware: ims.er.usgs.gov/gda_services/download?item_id=5368076" title="https:/-/web.archive.org/web/20170907215753ims.er.usgs.gov/gda_services/download?item_id=5368076">weblink The states had agreed on a resolution, and it was affirmed by an act of Congress on this date.HTTPS://BOOKS.GOOGLE.COM/BOOKS?ID=1S8PAAAAYAAJ&PG=PA104	YEAR=1921	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160409083458/HTTPS://BOOKS.GOOGLE.COM/BOOKS?ID=1S8PAAAAYAAJ&LPG=PR6&OTS=VKQZWGDPGF&PG=PA104	LAST1=STATES, United, JOURNAL, Hayes, J. Carroll, July 1923, The Delaware Curve: The Story of the Pennsylvania-Delaware Circular Boundary,journals.psu.edu/pmhb/article/viewFile/27979/27735, Pennsylvania Magazine of History and Biography, Historical Society of Pennsylvania, 47, 3, May 10, 2015, Some sources, both contemporary and modern, note that, in the original process of resurveying the border in 1892, a very thin, horn-shaped region along the arc was transferred from Delaware to Pennsylvania;NEWS,www.nytimes.com/1892/12/19/archives/refuse-to-be-expatriated-citizens-of-drlaware-decline-to-become.html, Refuse to be Expatriated: Citizens of Delaware Decline to Become Pennsylvanians, December 19, 1892, The New York Times, May 10, 2015, live,query.nytimes.com/gst/abstract.html?res=9F07E1DB1F31E033A2575AC1A9649D94639ED7CF," title="web.archive.org/web/20160305002733query.nytimes.com/gst/abstract.html?res=9F07E1DB1F31E033A2575AC1A9649D94639ED7CF,">web.archive.org/web/20160305002733query.nytimes.com/gst/abstract.html?res=9F07E1DB1F31E033A2575AC1A9649D94639ED7CF, March 5, 2016, however, no federal maps found reflect this, and it is unclear if this transfer actually occurred.	alt=Map of the change to the United States in central North America on June 30, 1921|250px)

!scope=row|May 10, 1922

Kingman Reef was formally annexed.HTTPS://WWW.DOI.GOV/OIA/ISLANDS/KINGMANREEF	OFFICE OF INSULAR AFFAIRS >TITLE=KINGMAN REEF	ACCESS-DATE=JULY 15, 2016	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160815122443/HTTPS://WWW.DOI.GOV/OIA/ISLANDS/KINGMANREEF, August 15, 2016,	no change to map

!scope=row|October 8, 1923|Michigan expanded its claim to Wisconsin territory, though Wisconsin never lost control over the area.

alt=Map of the change to the United States in central North America on October 8, 1923|250px)

!scope=row|November 15, 1923

Swan Islands, Honduras>Swan Islands were claimed by Honduras.Reply of the United States to the Honduran Claim of Sovereignty over the Swan Islands {{webarchive	images.library.wisc.edu/FRUS/EFacs/1940v05/reference/frus.frus1940v05.i0016.pdf >date=March 4, 2016 }}, accessed July 8, 2015	Caribbean Sea:(File:United States Caribbean change 1923-11-15.png	250px)

!scope=row|February 1, 1924

Alajuela Lake>Madden Lake was annexed to the Panama Canal Zone under the United States right of expropriation in the 1903 Canal Treaty.Van Zandt, pp. 58–60ANNUAL REPORT OF THE GOVERNOR OF THE PANAMA CANAL FOR THE FISCAL YEAR ENDED JUNE 30, 1924 >PAGE=13	PUBLISHER=[U.S.] GOVERNMENT PRINTING OFFICE	URL=HTTPS://ARCHIVE.ORG/DETAILS/ANNUALREPORTOFGO1924CANA		DATE = JUNE 5, 1924	POST = PRESIDENT OF THE UNITED STATES, June 30, 2015,	Caribbean Sea:(File:United States Caribbean change 1924-02-01.png	250px)

!scope=row|March 4, 1925

Swains Island was added to American Samoa.HTTP://LEGISWORKS.ORG/CONGRESS/68/PUBRES-75.PDF	YEAR=1925	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20151030103928/HTTP://LEGISWORKS.ORG/CONGRESS/68/PUBRES-75.PDF	ACCESS-DATE=JULY 1, 2016,	Pacific Ocean:(File:United States Pacific change 1925-03-04.png	250px)

!scope=row|July 17, 1925

Canada was adjusted in several places.HTTP://TREATIES.FCO.GOV.UK/DOCS/PDF/1925/TS0037.PDF	DATE=FEBRUARY 24, 1925	URL-STATUS=DEAD	ARCHIVE-DATE=AUGUST 16, 2016, Van Zandt, pp. 21–22 The only change to a land border redefined how the border between the Lake of the Woods and the Rocky Mountains should be considered; previously, the border followed the curve of the parallel between each border monument, while the treaty changed this to straight lines between each monument. Through this, the United States netted a gain of between 30 and 35 acres of land. Because of the extremely small shift, the lack of specific documentation of where the changes occurred, and the lack of any human impact, this change is not mapped. There was also a change to the border in the Lake of the Woods; a surveying anomaly caused the previous border to intersect itself several times in the lake, creating enclaves of United States water surrounded by Canadian water. The treaty changed the border to use the southernmost intersection as the northwestern point of the Lake of the Woods. Finally, the maritime border in the Bay of Fundy was adjusted, netting Canada roughly 9 acres of water.	too small to map

!scope=row|March 1, 1926

Supreme Court of the United States resolved the conflict between Michigan and Wisconsin in the favor of Wisconsin.{{ussc>name=Wisconsin v. Michigan	page=295|year=1926}}	alt=Map of the change to the United States in central North America on March 1, 1926|250px)

!scope=row|July 29, 1926

Johnston Atoll was established as a federal bird refuge and placed under the jurisdiction of the United States Department of Agriculture.4467	LANGUAGE=ENGLISH		PUBLISHER=U.S. DEPARTMENT OF THE INTERIOR OFFICE OF INSULAR AFFAIRS	date=September 2023	fix-attempted=yes }}	no change to map

!scope=row|November 22, 1926

Supreme Court of the United States defined the border between Michigan and Wisconsin, transferring all islands south of the Quinnesec Falls on the Menominee River to Wisconsin, and all islands north of the falls to Michigan; it is unknown specifically which islands were transferred in this fashion. However, an error in the border description introduced a small overlap between the two states over several islands in Lake Michigan north of the Door Peninsula.{{ussc>name=Wisconsin v. Michigan	page=398|year=1926}}	alt=Map of the change to the United States in central North America on November 22, 1926|250px)

!scope=row|July 18, 1927

Panama another 33 hectares of land on the islands of Taboga Island>Taboga and Taboguilla and annexed them to the Panama Canal Zone.	too small to map

!scope=row|October 26, 1927

Banco Convention of 1905>bancos along the Colorado River were ceded from Mexico to Arizona.HTTP://WWW.IBWC.GOV/FILES/MINUTES/MIN99.PDF >TITLE=MINUTE 99: RE ACCRETIONS LANDS ON COLORADO RIVER—ALSO FARMERS AND FAIN BANCOS.DECISION REACHED.	INTERNATIONAL BOUNDARY AND WATER COMMISSION >DATE=OCTOBER 26, 1927	URL-STATUS=LIVE	ARCHIVE-DATE=MARCH 4, 2016, HTTP://WWW.IBWC.STATE.GOV/TREATIES_MINUTES/MINUTES.HTML >TITLE=MINUTES BETWEEN THE UNITED STATES AND MEXICAN SECTIONS OF THE IBWC	INTERNATIONAL BOUNDARY AND WATER COMMISSION >ACCESS-DATE=JANUARY 6, 2016	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20150713015418/HTTP://WWW.IBWC.STATE.GOV/TREATIES_MINUTES/MINUTES.HTML, July 13, 2015,	too small to map

!scope=row|December 5, 1927

Country Club Dispute” between New Mexico and Texas was resolved in Texas’s favor.{{ussc>name=New Mexico v. Texas	page=279|year=1927}}	alt=Map of the change to the United States in Central North America on December 5, 1927|250px)

!scope=row|April 4, 1928

Island of Palmas Case was decided in the favor of the Netherlands, ceding Miangas>Palmas to the Dutch East Indies.Island of Palmas Case (Netherlands, USA) {{webarchive	legal.un.org/riaa/cases/vol_II/829-871.pdf >date=October 3, 2016 }}, April 4, 1928; accessed June 2, 2015	Pacific Ocean:(File:United States Pacific change 1928-04-04.png	250px)

!scope=row|September 24, 1928|The United States expropriated from Panama three hectares of land at El Cerro de Doscientos Pies (“200-Foot Hill“) near Las Minas Bay and annexed it to the Panama Canal Zone.

too small to map

!scope=row|July 22, 1930|The United States expropriated from Panama 25 hectares on Jicarita Island and 60 hectares at Punta Morro de Puercos and annexed them to the Panama Canal Zone.

too small to map

!scope=row|April 15, 1931|The United States expropriated from Panama additional areas around the soon-to-be-built Madden Dam and annexed them to the Panama Canal Zone.

Caribbean Sea:(File:United States Caribbean change 1931-04-15.png	250px)

!scope=row|May 3, 1932

Panama City#Neighborhoods>Punta Paitilla in the Canal Zone, returning a small amount of land to Panama. This was the site for a planned new American embassy, which had to be built on foreign soil.{{usstat	145}}	too small to map

!scope=row|May 17, 1932

Puerto Rico.{{UnitedStatesCode2>48	Change of name; Puerto Rico}}	Caribbean Sea:(File:United States Caribbean change 1932-05-17.png	250px)

!scope=row|December 13, 1932

Turtle Islands, Tawi-Tawi>Turtle Islands were Convention Between the United States and Great Britain (1930)	by the United Kingdom from North Borneo to the Insular Government of the Philippine Islands>Philippines. The islands were supposed to be included in the 1900 transfer of islands from Spain to the United States. Per the terms of the treaty, the United Kingdom continued to administer the islands until requested, and, after the Philippines’ independence, the Philippine government made such a request and took control.{{usstat	2198}}	Pacific Ocean:(File:United States Pacific change 1932-12-13.png	250px)

!scope=row|May 29, 1933

Supreme Court of the United States Vermont v. New Hampshire>ruled that the border between New Hampshire and Vermont was the low water mark of the west bank of the Connecticut River; Vermont had sought to have the border placed in the middle of the river.	no change to map

!scope=row|November 13, 1933

Rio Grande Rectification Project, which, from 1935 to 1938, straightened and stabilized the path of the Rio Grande through the El Paso, Texas>El Paso–Ciudad Juárez	Valley. By the end of the project, 174 parcels had been transferred between Mexico and Texas, each side receiving an equal area of land.HTTPS://BOOKS.GOOGLE.COM/BOOKS?ID=_5RQOOKRGY0C	TITLE=AMERICAN WATER RESOURCES ADMINISTRATION	LAST1=SHIH		PUBLISHER=INTERNATIONAL BOUNDARY AND WATER COMMISSION	URL-STATUS=DEAD	ARCHIVE-DATE=JUNE 16, 2015,	too small to map

!scope=row|December 29, 1934|Kingman Reef was placed under the jurisdiction of the United States Department of the Navy.

no change to map

!scope=row|November 15, 1935

Insular Government of the Philippine Islands was Tydings–McDuffie Act>dissolved and replaced with the Commonwealth of the Philippines.HTTPS://WWW.LAWPHIL.NET/EXECUTIVE/PROC/PROC1935/PROC_2148_1935.HTML > TITLE=PROCLAMATION 2148—ESTABLISHMENT OF THE COMMONWEALTH OF THE PHILIPPINES	ACCESSDATE=JANUARY 25, 2022	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20220125170409/HTTPS://WWW.LAWPHIL.NET/EXECUTIVE/PROC/PROC1935/PROC_2148_1935.HTML	48|456}}	Pacific Ocean:(File:United States Pacific change 1935-11-15.png	250px)

!scope=row|March 16, 1936

Michigan and Wisconsin was Wisconsin v. Michigan>resolved by the Supreme Court of the United States.{{ussc	volume=297	year=1936}}	alt=Map of the change to the United States in central North America on March 16, 1936|250px)

!scope=row|May 13, 1936

Baker Island, Howland Island, and Jarvis Island were formally annexed and placed under the jurisdiction of the United States Department of the Interior,7368	LANGUAGE=ENGLISH, President of the United States, ending the United Kingdom’s claim to Jarvis Island.	Pacific Ocean:(File:United States Pacific change 1936-05-13.png	250px)

!scope=row|June 22, 1936

U.S. Virgin Islands were Organic Act of the Virgin Islands of the United States>organized into a civil territory.{{usstat	1807}}	no change to map

!scope=row|August 6, 1936

Kanton Island>Canton Island, Enderbury Island, and McKean Island were claimed by the United Kingdom.	Pacific Ocean:(File:United States Pacific change 1936-08-06.png	250px)

!scope=row|April 6, 1939

Canton and Enderbury Islands was established with the United Kingdom.HTTPS://BOOKS.GOOGLE.COM/BOOKS?ID=YC8WAAAAYAAJ&PG=PA543	ACCESS-DATE=APRIL 12, 2015	FIRST1=CHARLES IRVING, 1976,	Pacific Ocean:(File:United States Pacific change 1939-04-06.png	250px)

!scope=row|July 27, 1939

Panama gained a sovereign corridor that was carved out of the Panama Canal Zone connecting Colón, Panama>Colón with the rest of Panama, along with a three-dimensional “tube” of sovereignty for a future crossing over an American highway. A corridor consisting of the road from the Canal Zone boundary to Madden Dam was annexed to the Canal Zone.HTTPS://WWW.LOC.GOV/LAW/HELP/US-TREATIES/BEVANS/B-PA-UST000010-0742.PDF >TITLE=TREATY OF FRIENDSHIP AND COOPERATION	ACCESS-DATE=NOVEMBER 2, 2016	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20161104004354/HTTPS://WWW.LOC.GOV/LAW/HELP/US-TREATIES/BEVANS/B-PA-UST000010-0742.PDF, November 4, 2016,	Caribbean Sea:(File:United States Caribbean change 1939-07-27.png	250px)

!scope=row|August 16, 1939

Fakaofo, Funafuti, Orona>Hull Island, Niulakita, Nukufetau, and Nukulaelae.FOREIGN RELATIONS OF THE UNITED STATES DIPLOMATIC PAPERS, GENERAL, THE BRITISH COMMONWEALTH AND EUROPE (1939) >PUBLISHER=U.S. DEPARTMENT OF STATE	PAGES=317–319	URL-STATUS=LIVE	ARCHIVE-DATE=MARCH 4, 2016,	Pacific Ocean:(File:United States Pacific change 1939-08-16.png	250px)

!scope=row|December 10, 1941

George McMillin surrendered Guam to the Empire of Japan>Japanese military.HTTP://WWW.GUAMPEDIA.COM/JAPANESE-OCCUPATION-OF-GUAM/ >TITLE=JAPANESE OCCUPATION OF GUAM	PUBLISHER=GUAMPEDIA	URL-STATUS=LIVE	ARCHIVE-DATE=APRIL 2, 2015,	Pacific Ocean:(File:United States Pacific change 1941-12-10.png	250px)

!scope=row|December 23, 1941

Wake Island surrendered to the Empire of Japan>Japanese military.	Pacific Ocean:(File:United States Pacific change 1941-12-23.png	250px)

!scope=row|March 26, 1942

Commonwealth of the Philippines>Philippines evacuated from the territory in the face of Japanese advance. A government-in-exile would be established in Washington, D.C., on May 17, 1942. The United States Army Forces in the Far East would surrender on April 9, 1942, following the Battle of Bataan, and the final military holdouts would surrender on May 6, 1942, following the Battle of Corregidor.	Pacific Ocean:(File:United States Pacific change 1942-03-26.png	250px)

!scope=row|October 14, 1943

Second Philippine Republic was established as a puppet state of Empire of Japan>Japan.	Pacific Ocean:(File:United States Pacific change 1943-10-14.png	250px)

!scope=row|August 10, 1944

Guam was Battle of Guam (1944)>captured from Japan.	Pacific Ocean:(File:United States Pacific change 1944-08-10.png	250px)

!scope=row|August 17, 1945

Second Philippine Republic, in exile in Tokyo since April 3, 1945, was dissolved. The process of re-establishing the Commonwealth government on Philippine soil had started on October 23, 1944.HTTP://MALACANANG.GOV.PH/5235-70TH-ANNIVERSARY-OF-THE-SECOND-PHILIPPINE-REPUBLIC/	PUBLISHER=REPUBLIC OF THE PHILIPPINES PRESIDENTIAL MUSEUM AND LIBRARY	URL-STATUS=DEAD	ARCHIVE-DATE=MARCH 15, 2015,	Pacific Ocean:(File:United States Pacific change 1945-08-17.png	250px)

!scope=row|September 4, 1945

Empire of Japan>Japanese garrison on Wake Island surrendered to the United States.HTTP://WWW.HISTORY.NAVY.MIL/OUR-COLLECTIONS/PHOTOGRAPHY/NUMERICAL-LIST-OF-IMAGES/NHHC-SERIES/NH-SERIES/NH-96000/NH-96813.HTML >TITLE=SURRENDER OF WAKE ATOLL, 4 SEPTEMBER 1945	NAVAL HISTORY & HERITAGE COMMAND >ACCESS-DATE=APRIL 11, 2015	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20161023112636/HTTPS://WWW.HISTORY.NAVY.MIL/OUR-COLLECTIONS/PHOTOGRAPHY/NUMERICAL-LIST-OF-IMAGES/NHHC-SERIES/NH-SERIES/NH-96000/NH-96813.HTML, October 23, 2016,	Pacific Ocean:(File:United States Pacific change 1945-09-04.png	250px)

“>

1946–present (Decolonization){|class“wikitable plainrowheaders”

!scope=“col“|Date!scope=“col“|Event!scope=“col“|Change map!scope=row|July 4, 1946

Commonwealth of the Philippines Treaty of Manila (1946)>became independent as the Philippines	.HTTPS://TREATIES.UN.ORG/DOC/PUBLICATION/UNTS/VOLUME%207/V7.PDF	ACCESS-DATE=APRIL 10, 2015	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20150924110851/HTTPS://TREATIES.UN.ORG/DOC/PUBLICATION/UNTS/VOLUME%207/V7.PDF, September 24, 2015,	Pacific Ocean:(File:United States Pacific change 1946-07-04.png	250px)

!scope=row|July 18, 1947

United Nations entrusted the Trust Territory of the Pacific Islands to the United States.11021	DATE=JULY 1, 1962	POST=PRESIDENT OF THE UNITED STATES, April 10, 2015,	Pacific Ocean:(File:United States Pacific change 1947-07-18.png	250px)

!scope=row|January 1, 1949

Tokelau>Tokelau Islands were incorporated into New Zealand, which inherited the claims on Atafu, Fakaofo, and Nukunono.Tokelau Act 1948 {{webarchive	www.legislation.govt.nz/act/public/1948/0024/1.0/DLM247577.html >date=August 16, 2016 }}, NZ Pub Act 1948 No. 24; accessed July 2, 2015	Pacific Ocean:(File:United States Pacific change 1949-01-01.png	250px)

!scope=row|August 1, 1950

Guam was Guam Organic Act of 1950>organized into a civil territory.HTTP://WWW.GUAMPEDIA.COM/ORGANIC-ACT-OF-GUAM/ >TITLE=ORGANIC ACT OF GUAM	PUBLISHER=GUAMPEDIA	URL-STATUS=LIVE	ARCHIVE-DATE=APRIL 2, 2015, {{usstat	384}}	no change to map

!scope=row|August 3, 1950

Kansas and Missouri exchanged small portions of land along the Missouri River, to accord with shifts in the river following a flood in 1944.{{usstat>64|397}}	alt=Map of the change to the United States in central North America on August 3, 1950|250px)

!scope=row|April 11, 1955

Colón, Panama>Colón with the rest of Panama was realigned within the Panama Canal Zone. Several three-dimensional “tubes” of sovereignty were also created, allowing Panamanian bridges to pass over rivers and a highway at several locations within the Canal Zone.Convention between the United States of America and the Republic of Panama regarding the Colon Corridor and certain other corridors through the Canal Zone {{webarchive	treaties.un.org/doc/Publication/UNTS/Volume%20241/v241.pdf >date=March 4, 2016 }}, signed May 24, 1950; United Nations Treaty Series	3430; accessed June 30, 2015EVGENY	TITLE = THEORY OF ENCLAVES	PUBLISHER = LEXINGTON BOOKS, LANHAM, MD	URL= HTTPS://BOOKS.GOOGLE.COM/BOOKS?ID=DCIXBGTKMWUC&PG=PA190	ISBN=978-0-7391-2403-1,	too small to map

!scope=row|August 23, 1955

Panama Canal Zone were redefined. Punta Paitilla, the land held on Taboga Island, and the remaining American holdings in Colón, Panama>Colón and Panama City were ceded to Panama.Treaty of mutual understanding and co-operation between the United States of America and the Republic of Panama {{webarchive	treaties.un.org/doc/Publication/UNTS/Volume%20243/v243.pdf >date=August 21, 2016 }}, signed January 25, 1955; UNTS 3454; accessed June 30, 2015	Caribbean Sea:(File:United States Caribbean change 1955-08-23.png	250px)

!scope=row|January 3, 1959|The Alaska Territory was admitted as the forty-ninth state, Alaska.

Northwestern North America:(File:United States Northwest change 1959-01-03.png	250px)

!scope=row|August 21, 1959|Most of Hawaii Territory was admitted as the fiftieth state, Hawaii. Palmyra Atoll was excluded from statehood and remained a territory.

Pacific Ocean:(File:United States Pacific change 1959-08-21.png	250px)

!scope=row|August 25, 1961

Minnesota to North Dakota near Fargo, North Dakota.{{usstat>75|399}}	too small to map

!scope=row|January 14, 1964

Chamizal, a tract of land between El Paso, Texas, and Ciudad Juárez, Chihuahua, was divided between the United States and Mexico.HTTP://WWW.IBWC.GOV/FILES/CHAMIZALCONVENTION1963.PDF	DATE=AUGUST 29, 1963	PUBLISHER=INTERNATIONAL BOUNDARY AND WATER COMMISSION	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20141219222000/HTTP://WWW.IBWC.GOV/FILES/CHAMIZALCONVENTION1963.PDF, December 19, 2014,	alt=Map of the change to the United States in central North America on January 14, 1964|250px)

!scope=row|August 4, 1965

Cook Islands became self-governing from New Zealand. It claimed the atolls of Manihiki, Penrhyn (atoll)>Penrhyn, Pukapuka, and Rakahanga.HTTP://WWW.PARLIAMENT.GOV.CK/CONSTITUTION.PDF >TITLE=CONSTITUTION OF THE COOK ISLANDS	URL-STATUS=DEAD	ARCHIVE-DATE=SEPTEMBER 24, 2015,	Pacific Ocean:(File:United States Pacific change 1965-08-04.png	250px)

!scope=row|December 30, 1966|Land on Diego Garcia in the Indian Ocean was leased from the United Kingdom for use as a military base.Van Zandt p. 43

no change to map

!scope=row|April 25, 1971|The lease of the Corn Islands from Nicaragua was terminated.

no change to map

!scope=row|September 1, 1972

Swan Islands, Honduras>Swan Islands.WEB ,treaties.un.org/doc/Publication/UNTS/Volume%20851/volume-851-I-12199-English.pdf , Treaty on the Swan Islands , June 17, 2015 , live ,web.archive.org/web/20160821215204/https://treaties.un.org/doc/Publication/UNTS/Volume%20851/volume-851-I-12199-English.pdf , August 21, 2016 ,	Caribbean Sea:(File:United States Caribbean change 1972-09-01.png	250px)

!scope=row|March 1, 1977

Magnuson–Stevens Fishery Conservation and Management Act>claimed maritime borders west of the Strait of Juan de Fuca, within the Dixon Entrance, and in the Beaufort Sea that conflicted with claims of Canada.HTTP://WWW.DUR.AC.UK/RESOURCES/IBRU/PUBLICATIONS/FULL/BSB5-3_GRAY.PDF >TITLE=CANADA’S UNRESOLVED MARITIME BOUNDARIES	LAST=GRAY	WORK= IBRU BOUNDARY AND SECURITY BULLETIN	ACCESS-DATE=MARCH 21, 2015,	no change to map

!scope=row|May 26, 1977

Boundary Treaty of 1970>exchanged between Texas and Mexico along the Rio Grande in areas near Presidio, Texas

and Hidalgo, Texas,HTTP://WWW.IBWC.GOV/TREATIES_MINUTES/MINUTES.HTML

PUBLISHER=INTERNATIONAL BOUNDARY AND WATER COMMISSION

URL-STATUS=LIVE

ARCHIVE-DATE=NOVEMBER 18, 2016, including the Horcón Tract, on which the town of Río Rico, Tamaulipas

was located,SEPTEMBER 26, 1987

TITLE=SOUTH OF BORDER WAS ONCE NORTH

NEW YORK TIMES >ACCESS-DATE=NOVEMBER 11, 2013

URL-STATUS=LIVE

ARCHIVE-DATE=MARCH 9, 2014, and Beaver Island near Roma, Texas. In addition, Mexico ceded {{convert

acre

2177

km2}} to Mexico, primarily to straighten sections of the Rio Grande for flood control.HTTPS://WWW.IBWC.GOV/FILES/MINUTES/MIN257.PDF>TITLE=COMPLETION OF THE RELOCATIONS OF THE RIO GRANDE STIPULATED IN ARTICLE I OF THE TREATY OF NOVEMBER 23, 1970 (MINUTE NO. 257)

INTERNATIONAL BOUNDARY AND WATER COMMISSION>DATE=MAY 18, 1977

ARCHIVE-DATE=APRIL 7, 2016

URL-STATUS=DEAD,

alt=Map of the change to the United States in central North America on May 26, 1977|250px)

!scope=row|December 16, 1977

Cuba–United States Maritime Boundary Agreement>treaty defining the maritime border with Cuba was signed; though it has never been ratified by the United States Senate, it is provisionally enforced by agreement renewed every two years.	no change to map

!scope=row|October 1, 1978

Tuvalu became independent from the United Kingdom. It claimed the atolls of Funafuti, Nukufetau, Nukulaelae, and Niulakita.HTTP://WWW.PACLII.ORG/TV/LEGIS/CONSOL_ACT/COT277/	ACCESS-DATE=JULY 2, 2015	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20150828063609/HTTP://WWW.PACLII.ORG/TV/LEGIS/CONSOL_ACT/COT277/, August 28, 2015,	Pacific Ocean:(File:United States Pacific change 1978-10-01.png	250px)

!scope=row|July 12, 1979

Kiribati>Republic of Kiribati became independent from the United Kingdom. It claimed Birnie Island, Kanton Island	, Caroline Island, Kiritimati>Christmas Island, Enderbury Island, Flint Island, Nikumaroro	, Orona>Hull Island, Malden Island, McKean Island, Rawaki Island	, Starbuck Island, Manra Island>Sydney Island, and Vostok Island. This dissolved the condominium of the Canton and Enderbury Islands.HTTP://WWW.PARLIAMENT.GOV.KI/CONTENT/CONSTITUTION-KIRIBATI >TITLE=CONSTITUTION OF KIRIBATI	ACCESS-DATE=APRIL 9, 2015	URL-STATUS=DEAD	ARCHIVE-DATE=SEPTEMBER 21, 2015,	Pacific Ocean:(File:United States Pacific change 1979-07-12.png	250px)

!scope=row|October 1, 1979

Panama Canal Zone was Torrijos–Carter Treaties>ceded to Panama. The United States and Panama continued to share operational control of the canal until December 31, 1999, when it would be fully turned over to Panama.HTTPS://HISTORY.STATE.GOV/MILESTONES/1977-1980/PANAMA-CANAL >PUBLISHER=U.S. DEPARTMENT OF STATE	ACCESS-DATE=APRIL 9, 2015	URL-STATUS=LIVE	ARCHIVE-DATE=NOVEMBER 8, 2014, The United States retained control over several hundred specified areas to be turned over in piecemeal fashion over the years.	Caribbean Sea:(File:United States Caribbean change 1979-10-01.png	250px)

!scope=row|November 24, 1980

Venezuela was defined.Maritime Boundary Treaty {{webarchive>url=https://web.archive.org/web/20160304204522treaties.un.org/doc/Publication/UNTS/Volume%201273/v1273.pdf	United Nations Treaty Series>UNTS 20984; accessed June 30, 2015	no change to map

!scope=row|September 17, 1981|The United States recognized the sovereignty of Colombia over Roncador Bank and Serrana Bank, and the claim on Quita Sueño Bank was abandoned by the United States, as it was no longer above the seas at high tide, and thus the government considered it unclaimable.WEB ,

Caribbean Sea:(File:United States Caribbean change 1981-09-17.png	250px)

!scope=row|September 3, 1983

Treaty of Tokehega>recognized the sovereignty of the New Zealand territory of Tokelau over Atafu, Fakaofo, and Nukunono, and defined the maritime border with Tokelau.WEB ,treaties.un.org/doc/Publication/UNTS/Volume%201643/v1643.pdf , Treaty between the United States of America and New Zealand on the Delimitation of the Maritime Boundary between Tokelau and the United States of America , 251–267 , June 17, 2015 , live ,web.archive.org/web/20160304230003/https://treaties.un.org/doc/Publication/UNTS/Volume%201643/v1643.pdf , March 4, 2016 ,	Pacific Ocean:(File:United States Pacific change 1983-09-03.png	250px)

!scope=row|September 8, 1983

Cook Islands–United States Maritime Boundary Treaty>recognized the sovereignty of the Cook Islands over Manihiki, Penrhyn, Pukapuka, and Rakahanga, and the maritime border with the Cook Islands was defined.WEB,2009-2017.state.gov/documents/organization/125388.pdf, Treaty between the United States of America and the Cook Islands, June 11, 1980, April 8, 2015,	Pacific Ocean:(File:United States Pacific change 1983-09-08.png	250px)

!scope=row|September 23, 1983

Treaty of Tarawa>recognized the sovereignty of Kiribati over Birnie Island, Kanton Island	, Caroline Island, Kiritimati>Christmas Island, Enderbury Island, Flint Island, Nikumaroro	, Orona>Hull Island, Malden Island, McKean Island, Rawaki Island	, Starbuck Island, Manra Island>Sydney Island, and Vostok Island.HTTPS://WWW.DOI.GOV/OIA/ISLANDS/DISPUTEDISLANDS >TITLE=FORMERLY DISPUTED ISLANDS	PUBLISHER=U.S. DEPARTMENT OF THE INTERIOR OFFICE OF INSULAR AFFAIRS	URL-STATUS=LIVE	ARCHIVE-DATE=MARCH 5, 2016, WEB ,treaties.un.org/doc/Publication/UNTS/Volume%201643/v1643.pdf , Treaty of Friendship between the United States of America and the Republic of Kiribati , 239–250 , June 17, 2015 , live ,web.archive.org/web/20160304230003/https://treaties.un.org/doc/Publication/UNTS/Volume%201643/v1643.pdf , March 4, 2016 , The United States recognized the sovereignty of Tuvalu over Funafuti, Nukufetau, Nukulaelae, and Niulakita.WEB ,treaties.un.org/doc/Publication/UNTS/Volume%202011/v2011.pdf , Treaty of Friendship between the United States of America and Tuvalu , 79–84 , June 17, 2015 , live ,web.archive.org/web/20160304200403/https://treaties.un.org/doc/Publication/UNTS/Volume%202011/v2011.pdf , March 4, 2016 ,	Pacific Ocean:(File:United States Pacific change 1983-09-23.png	250px)

!scope=row|October 12, 1984|The International Court of Justice made its judgment on where the maritime border should be in the Gulf of Maine between the United States and Canada.Case Concerning Delimitation of the Maritime Boundary in the Gulf of Maine Area (Canada v. United States) {{Webarchive|url=https://web.archive.org/web/20160817084511www.icj-cij.org/docket/index.php?p1=3&p2=3&k=6f&case=67&code=cigm&p3=4 |date=August 17, 2016 }} , accessed June 30, 2015

no change to map

!scope=row|October 21, 1986

Trust Territory of the Pacific Islands became independent as the Marshall Islands>Republic of the Marshall Islands. The Marshall Islanders had claimed Wake Island as part of their territory since at least 1973, and continued that after independence.ANDERSON >FIRST=JON	TITLE=WAKE ISLAND CLAIMED BY MARSHALL ISLANDERS	ACCESS-DATE=JANUARY 28, 2016	LOCATION=CAMERON, TEXAS	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160819040955/HTTPS://WWW.NEWSPAPERS.COM/CLIP/3864881/WAKE_ISLAND_CLAIMED_BY_MARSHALL_ISLANDS/, August 19, 2016,	Pacific Ocean:(File:United States Pacific change 1986-10-21.png	250px)

!scope=row|November 3, 1986

Trust Territory of the Pacific Islands was dissolved by the United Nations. The districts of Chuuk, Pohnpei, and Yap became independent as the Federated States of Micronesia. The Mariana Islands District, having already been taking moves towards integration with the United States, became a territory of the United States, the Northern Mariana Islands>Commonwealth of the Northern Mariana Islands.HTTP://WWW.GPO.GOV/FDSYS/PKG/STATUTE-101/PDF/STATUTE-101-PG2027.PDF >TITLE=PROCLAMATION 5564: PLACING INTO FULL FORCE AND EFFECT THE COVENANT WITH THE COMMONWEALTH OF THE NORTHERN MARIANA ISLANDS, AND THE COMPACTS OF FREE ASSOCIATION WITH THE FEDERATED STATES OF MICRONESIA AND THE REPUBLIC OF THE MARSHALL ISLANDS	DATE=NOVEMBER 3, 1986	PUBLISHER=GOVERNMENT PUBLISHING OFFICE	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160924011909/HTTPS://WWW.GPO.GOV/FDSYS/PKG/STATUTE-101/PDF/STATUTE-101-PG2027.PDF	AUTHOR-LINK=RONALD REAGAN,	Pacific Ocean:(File:United States Pacific change 1986-11-03.png	250px)

!scope=row|June 1, 1990

Soviet Union was provisionally defined.HTTPS://WWW.UN.ORG/DEPTS/LOS/LEGISLATIONANDTREATIES/PDFFILES/TREATIES/USA-RUS1990MB.PDF	DATE=1 JUNE 1990	Agreement between the United States of America and the Union of Soviet Socialist Republics to abide by the terms of the Maritime Boundary Agreement of 1 June 1990, pending entry into force {{webarchive>url=https://web.archive.org/web/20160821224834treaties.un.org/doc/Publication/UNTS/Volume%202262/v2262.pdf	United Nations Treaty Series>UNTS 40300; accessed July 1, 2015 but while it was ratified by the United States Senate on September 16, 1991,{{USTreaty	22}} it was never ratified by the Soviet Union or its successor state, Russia.	no change to map

!scope=row|October 1, 1994

Trust Territory of the Pacific Islands, the Palau District, became independent as the Palau>Republic of Palau, dissolving the TTPI.PALAU GAINS INDEPENDENCE ON SATURDAY >AGENCY=ASSOCIATED PRESS	DATE=SEPTEMBER 30, 1994,news.google.com/newspapers?id=LOZHAAAAIBAJ&pg=5945,7792568&dq=palau&hl=en,	Pacific Ocean:(File:United States Pacific change 1994-10-01.png	250px)

!scope=row|June 1, 1995

United Kingdom in the Caribbean Sea was defined.Treaty on the delimitation in the Caribbean of a maritime boundary relating to the U.S. Virgin Islands and Anguilla {{webarchive>url=https://web.archive.org/web/20160331131528treaties.un.org/doc/Publication/UNTS/Volume%201913/v1913.pdf	United Nations Treaty Series>UNTS 32636; accessed July 1, 2015Treaty on the delimitation in the Caribbean of a maritime boundary relating to Puerto Rico/U.S. Virgin Islands and the British Virgin Islands {{webarchive	treaties.un.org/doc/Publication/UNTS/Volume%201913/v1913.pdf >date=March 31, 2016}}, signed May 11, 1993; UNTS 32637; accessed July 1, 2015	no change to map

!scope=row|January 16, 1997

Navassa Island was transferred to the United States Department of the Interior.HTTPS://WWW.DOI.GOV/OIA/ISLANDS/NAVASSA	DATE=12 JUNE 2015	U.S. DEPARTMENT OF THE INTERIOR OFFICE OF INSULAR AFFAIRS >ACCESS-DATE=JULY 15, 2016	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160815201647/HTTPS://WWW.DOI.GOV/OIA/ISLANDS/NAVASSA	Secretary’s Orders 3205: Administration of Navassa Island{{Dead link>date=January 2023	fix-attempted=yes }}, United States Secretary of the Interior Bruce Babbitt, signed January 16, 1997, accessed June 30, 2015	no change to map

!scope=row|November 13, 1997

Mexico was defined.Treaty on maritime boundaries between the United Mexican States and the United States of America {{webarchive>url=https://web.archive.org/web/20160304140922treaties.un.org/doc/Publication/UNTS/Volume%202143/v2143.pdf	United Nations Treaty Series>UNTS 37399; accessed June 30, 2015	no change to map

!scope=row|May 26, 1998

Supreme Court of the United States>Supreme Court New Jersey v. New York	that extra land added to Ellis Island since the original island was officially granted to New York (state)>New York in an interstate compact with New Jersey in 1834 belonged to New Jersey, owing to the fact that the island was within the territorial waters of New Jersey. The original natural boundary of Ellis Island remained an enclave of New York.HTTP://SUPREME.JUSTIA.COM/CASES/FEDERAL/US/523/767/>TITLE=NEW JERSEY V. NEW YORK – 523 U.S. 767 (1998)	ACCESS-DATE=AUGUST 2, 2012,	(File:United States Central change 1998-05-26.png	250px)

!scope=row|December 31, 1999|All former Panama Canal Zone parcels not turned over since 1979, as well as all joint canal operations areas, were transferred to Panama.

too small to map

!scope=row|January 17, 2001

Mexico on the continental shelf in the western Gulf of Mexico beyond 200 nautical miles was defined.Treaty between the Government of the United Mexican States and the Government of the United States of America on the delimitation of the continental shelf in the western Gulf of Mexico beyond 200 nautical miles {{webarchive>url=https://web.archive.org/web/20160304140922treaties.un.org/doc/Publication/UNTS/Volume%202143/v2143.pdf	United Nations Treaty Series>UNTS 37400; accessed June 30, 2015	no change to map

!scope=row|November 24, 2009

Rio Grande were ceded from Texas to Mexico, and three islands and two bancos were ceded from Mexico to Texas. The transfer, which had been pending for 20 years, was the first application of Article III of the 1970 Boundary Treaty.HTTP://WWW.IBWC.STATE.GOV/FILES/MINUTES/JOINT_REPORT_315.PDF	PUBLISHER=INTERNATIONAL BOUNDARY AND WATER COMMISSION	ACCESS-DATE=JUNE 13, 2016	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160411202233/HTTP://WWW.IBWC.STATE.GOV/FILES/MINUTES/JOINT_REPORT_315.PDF, April 11, 2016,	too small to map

!scope=row|September 23, 2014

Niue was Niue–United States Maritime Boundary Treaty>defined.{{USTreaty	53}} The treaty was signed on May 13, 1997, but it was not ratified by the United States until at least 2002, and the United Nations shows it as entering into force on this date.HTTPS://TREATIES.UN.ORG/PAGES/SHOWDETAILS.ASPX?OBJID=08000002804248EE >TITLE=TREATY BETWEEN THE GOVERNMENT OF NIUE AND THE GOVERNMENT OF THE UNITED STATES OF AMERICA ON THE DELIMITATION OF A MARITIME BOUNDARY	UNITED NATIONS >ACCESS-DATE=JUNE 30, 2015	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160821191110/HTTPS://TREATIES.UN.ORG/PAGES/SHOWDETAILS.ASPX?OBJID=08000002804248EE, August 21, 2016,	no change to map

!scope=row|January 1, 2017

North Carolina and South Carolina was clarified following years of surveys and negotiation, moving 19 homes across state lines.HTTP://ABC7NY.COM/NEWS/BORDER-OF-NORTH-AND-SOUTH-CAROLINA-SHIFTED-ON-JANUARY-1ST/1678605/	WORK=WABC	ACCESS-DATE=JANUARY 3, 2017	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20170103131022/HTTP://ABC7NY.COM/NEWS/BORDER-OF-NORTH-AND-SOUTH-CAROLINA-SHIFTED-ON-JANUARY-1ST/1678605/		WORK=THE NEW YORK TIMES	ACCESS-DATE=JANUARY 3, 2017	ARCHIVE-URL=HTTPS://WEB.ARCHIVE.ORG/WEB/20160524000946/HTTP://WWW.NYTIMES.COM/2014/08/24/OPINION/SUNDAY/HOW-THE-CAROLINAS-FIXED-THEIR-BLURRED-LINES.HTML, May 24, 2016,	too small to map

!scope=row|November 30, 2020

Rhode Island>State of Rhode Island and Providence Plantations adopted a constitutional amendment, renaming itself the State of Rhode Island.Rhode Island to Remove Word ‘Plantations’ From Official NameRI elections panel certifies Biden’s win, other races	(File:United States Central change 2020-11-30.png	250px)

Bancos along the Rio Grande

(File:Kanuti River October 2011.jpg|thumb|300px|An example of a banco, created when a meander is cut off by a new, shorter channel, leaving a cut-off section of land surrounded by a U-shaped (oxbow) lake)The Banco Convention of 1905 between the United States and Mexico allowed, in the event of sudden changes in the course of the Rio Grande (as by flooding), for the border to be altered to follow the new course.WEB,www.ibwc.state.gov/Files/Convention_of_1905.pdf, Convention Between the United States and Mexico for the Elimination of the Bancos in the Rio Grande from the Effects of Article II of the Treaty of November 12, 1884, June 5, 1907, April 19, 2015, dead,www.ibwc.state.gov/Files/Convention_of_1905.pdf," title="web.archive.org/web/20151009042029www.ibwc.state.gov/Files/Convention_of_1905.pdf,">web.archive.org/web/20151009042029www.ibwc.state.gov/Files/Convention_of_1905.pdf, October 9, 2015, The sudden changes often created bancos (land surrounded by bends in the river that became segregated from either country by a cutoff, often due to rapid accretion or avulsion of the alluvial channel), especially in the Lower Rio Grande Valley. When these bancos are created, the International Boundary and Water Commission investigates if land previously belonging to the United States or Mexico is to be considered on the other side of the border.WEB, Metz, Leon C., June 12, 2010, Bancos of the Rio Grande,www.tshaonline.org/handbook/online/articles/rnb08, Handbook of Texas Online, Texas State Historical Association, July 13, 2015,web.archive.org/web/20161027194705/https://www.tshaonline.org/handbook/online/articles/rnb08%29, October 27, 2016, live, In all cases of these adjustments along the Rio Grande under the 1905 convention, which occurred on 37 different dates from 1910 to 1976, the transferred land was minuscule (ranging from one to 646 acres) and uninhabited.WEB,www.ibwc.gov/Treaties_Minutes/Minutes.html, IBWC Minutes, International Boundary and Water Commission, September 11, 2017, WEB,www.google.com/maps/d/edit?mid=zTEHCtUumBXk.k-ueCthwuSNs, USA-Mexico Bancos Map, September 11, 2017, BOOK, Restless River, International Law and the Behavior of the Rio Grande, Texas Western Press, Mueller, Jerry E., 1975, 64, 9780874040500,

See also

{{commons category|Maps of the territorial evolution of the United States}}

• Geography of the United States
• Territories of the United States
• Historic regions of the United States
• American frontier
• List of U.S. state partition proposals
• List of U.S. states by date of admission to the Union
• Movements for the annexation of Canada to the United States
• National Atlas of the United States
• Ostend Manifesto (annexation of Cuba)
• List of territorial claims and designations in Colorado
• Territorial evolution of Arizona
• Territorial evolution of California
• Territorial evolution of Idaho
• Territorial evolution of Montana
• Territorial evolution of Nevada
• Territorial evolution of New Mexico
• Territorial evolution of North Dakota
• Territorial evolution of Oregon
• Territorial evolution of South Dakota
• Territorial evolution of Utah
• Territorial evolution of Washington
• Territorial evolution of Wyoming
• Territories of the United States on stamps
• List of U.S.–Native American treaties, which indicates tribal land cessions

Notes

{{notelist}}

References

{{reflist}}

Further reading

• BOOK, Rohrbough, M. J., 1978, The Trans-Appalachian Frontier: People, Societies, and Institutions, 1775-1850, The Trans-Appalachian Frontier: People, Societies, and Institutions, 1775-1850, Malcolm J. Rohrbough, Oxford University Press, 978-0-19-502209-4,
• BOOK, Stein, Mark, Mark Stein (author), 2008, How the States Got Their Shapes,books.google.com/books?id=w6UQZLmZ6LEC, New York, Smithsonian Books/Collins, 978-0-06-143138-8, 137324984,
• BOOK, Van Zandt, Franklin K., 1976,archive.org/details/bub_gb_skxAAAAAIAAJ, Boundaries of the United States and the Several States: With Miscellaneous Geographic Information Concerning Areas, Altitudes, and Geographic Centers, Washington, D.C., U.S. Government Printing Office, 69426475,
• BOOK, Statistical Atlas of the United States, 65–79, Walker, Francis A., 1874, [New York] J. Bien, lith.,archive.org/details/statisticalatla00unit/page/n5, April 3, 2019,

{{Territorial evolution of the world}}{{United States topics}}{{US history}}{{American frontier}}{{Thirteen Colonies}}{{Territories of the United States}}{{Former sovereign or unrecognized states within the United States}}{{featured list}}