Territorial evolution of the United States

This is a list of the evolution of the borders of the United States. This lists each change to the internal and external borders of the country, as well as status and name changes. It also shows the surrounding areas that eventually became part of the United States. Each situation has a map, to show what the specific makeup of the country was at any given time.

After achieving independence with the Treaty of Paris, the United States expanded westward, enlarging its borders seven times, with two major border adjustments, one each with colonies of the United Kingdom and Spain, and several small disputes. The original thirteen states grew into fifty states, most of which began as incorporated territories. The general pattern seen in this is of territorial expansion, carving of organized territories from the newly acquired land, modification of the borders of these territories, and eventual statehood. Only two states, Nevada and Missouri, grew appreciably after statehood, and four, Massachusetts, North Carolina, Texas, and Virginia, lost land, in each case to form new states.

Notes

*This article does not include unincorporated territories and countries under free association. The fundamental difference between "unincorporated" and "incorporated" territories is that incorporated territories are considered to forever be under the jurisdiction of the United States Constitution, whereas it is possible for unincorporated territories to become independent. These are:
**Nations under Compacts of Free Association: Marshall Islands, Federated States of Micronesia, Palau.
**Unincorporated, organized territories: Guam, United States Virgin Islands.
**Commonwealths, another form of unincorporated and organized territory: Northern Mariana Islands, Puerto Rico (This is different from the term "commonwealth" used by some states.)
**American Samoa is unorganized, but has a constitution and self-government, making it functionally very similar to an organized territory.
**The United States Minor Outlying Islands, which are uninhabited, unorganized, and except for Palmyra Atoll, unincorporated.
**The former unincorporated territories of the Line Islands, Panama Canal Zone, the Commonwealth of the Philippines, and the Phoenix Islands.
**The Trust Territory of the Pacific Islands, a United Nations trusteeship granted to the United States following World War II. It has since dissolved, becoming the Marshall Islands, Federated States of Micronesia, the Northern Mariana Islands, and Palau.
*"Unorganized territory" is not a name; it simply means Congress has not passed an organic act for the territory. In most situations, the purpose of unorganized territory was to act as land for Native American settlement. Later, the last unorganized territory in the country was indeed referred to as "Indian Territory", though this is not an official name. The last territories acquired by the United States, Alaska, Hawaii, and the Mexican Cession, began unorganized, but not as land set aside for Native Americans, but simply because they had not been organized yet.
*Dotted lines on the borders mean that region is part of a country not fully shown on the map, since it's confined to the present-day borders of the United States. An exception is Oregon Country, which was shared land which extended beyond the area of the map.
*Some territorial disputes and borders from early in the United States' history are unclear. For example, the border between West Florida and East Florida seems unclear. For the purposes of simplicity, this article uses the original border, the Apalachicola River, even though later maps tended to move it west to the Perdido River. This is partly because the Organic Act for Florida specified that it included parts of both West and East Florida; if the border were the Perdido River, then Florida Territory would not have included any of West Florida, it having already been divided among Louisiana, Mississippi, and Alabama.cite web
url=http://memory.loc.gov/cgi-bin/ampage?collId=llsl&fileName=003/llsl003.db&recNum=695
title=Text of the Organic Act for Florida Territory
accessdate=2006-08-04]
*Several very small changes are included in the list but not included in the maps.
#The switch of two extra counties from Virginia to West Virginia at the end of the American Civil War.
#The Alaska Boundary Dispute, since it arose from a total lack of surveying, rather than a dispute over the surveyed lines; it would also appear quite small on the map.
#The dispute over The Wedge, a square mile of land claimed by Pennsylvania and Delaware.
#When the Dakota Territory was created, it also included land south of 43° N and north of the Keya Paha and Niobrara rivers. This was transferred to the state of Nebraska on March 28 1882. [http://www.rootsweb.com/~neresour/OLLibrary/MWHNE/mwhne388.htm]
#The two small adjustments to Indiana Territory.
#Various disputes along the Rio Grande with Mexico.

18th century

;March 4 1789The United States Constitution came into effect, forming the new nation. Note that the states ratified at different times, but to simplify the map, the final result is shown here.

The United States achieved independence from the Kingdom of Great Britain with the Treaty of Paris on September 3 1783, which established that the thirteen colonies were sovereign and independent states. The borders were established by Article 2 of the treaty, but with a couple of issues. First, it stated that the border would run west from the Lake of the Woods to the Mississippi River - at the time, it was not known that the headwaters of the Mississippi lay south of such a line, so the border has since been taken to run south from the lake to the river. [cite web
url=http://www.yale.edu/lawweb/avalon/diplomacy/britain/paris.htm
title=Text of "The Paris Peace Treaty of September 3, 1783"
publisher=The Avalon Project at Yale Law School
accessdate=2006-08-06]

Some peculiarities to point out to those familiar only with the current borders: Many states had sea-to-sea grants from the British crown that they would not give up easily, so prior to this date, they ceded this land to the federal government in exchange for their Revolutionary War debts. However, Georgia did not do so until much later, and Connecticut ceded most land but kept its Western Reserve. Virginia ceded its claim to the territory north and west of the Ohio River, and this land became unorganized territory. North Carolina also ceded its claim to its western counties, but this was not officially accepted by Congress until 1790. New York ceded its claim on the Erie Triangle to the federal government. At this point in history, all of the states except for Georgia and Virginia were at their present-day borders, except for some of the minor issues mentioned above.

West Florida claimed a border further north than what the United States said it had. Its border had been 31° north when Spain ceded it to the United Kingdom. The British later moved its border north to 32°38' latitude, but when Spanish Florida was ceded back to Spain in the Treaty of Paris, the British cited the original border at the 31st parallel, but Spain continued to claim the higher border.cite web
url=http://dbwf.net/history/
title=Dominion of British West Florida History Index
accessdate=2006-08-04] Also, the borders at the northern area of the Maine District of Massachusetts and the area northwest of Lake Superior remained disputed.

The Wedge, disputed since the 17th century, remained a point of contention between Delaware and Pennsylvania.

The Vermont Republic was a complex matter, with areas being claimed by New York and New Hampshire, but it existed as a "de facto" unrecognized independent nation.

;August 7 1789The United States Congress affirmed the organization of the Territory North West of the Ohio River, or Northwest Territory, under the terms of the Northwest Ordinance. [cite web
url=http://rs6.loc.gov/cgi-bin/ampage?collId=llsl&fileName=001/llsl001.db&recNum=173
title=Statutes at Large, 1st Congress, 1st Session
publisher=Library of Congress
accessdate=2006-08-04] Northwest Territory consisted of present-day Illinois, Indiana, Michigan, northeastern Minnesota, most of Ohio, and Wisconsin. The Northwest Territory had previously been organized under the Articles of Confederation on July 13 1787, and was slightly modified under the new Constitution.

;April 2 1790Congress accepts North Carolina's cession of its western counties, which had initially been ceded on December 22 1789. The land became unorganized territory. [cite book
last= von Holst
first= Hermann
title=The Constitutional and Political History of the United States
publisher=Callaghan and Company
date=1877
pages= 809
url=http://books.google.com/books?id=DewJAAAAIAAJ&pg=PA309&lpg=PA309&dq=%22april+2+1790%22&source=web&ots=WaaPtx53QL&sig=D90XChYferMzmkYIAtiCOSe7DXE]

;May 26 1790The Southwest Ordinance organized the Territory South of the Ohio River, or Southwest Territory, which corresponded to present-day Tennessee. [cite web
url=http://www2.volstate.edu/cbucy/History%202030/Documents/Southwest%20Territory%20-%2023.htm
title=Text of the "Act for Government of the Southwest Territory"
accessdate=2006-08-04]

;March 4 1791The Vermont Republic, which had portions claimed by New York and New Hampshire and, while unrecognized by the United States, was a "de facto" independent country, was admitted as the 14th state, Vermont.

;September 9 1791The District of Columbia, the nation's federal district, was formed from land granted by Maryland and Virginia; the Virginia portion would be returned in 1847. [cite web
url=http://www.citymuseumdc.org/gettoknow/faq.asp
title=Frequently Asked Questions About Washington, D.C.
publisher=The Historical Society of Washington, DC
accessdate=2006-08-04]

;March 3 1792The federal government sold the Erie Triangle to Pennsylvania. [cite web
url=http://www.rootsweb.com/~paerie/land/TriangleMonumentHistory.htm
title=Erie County (PA) Genealogy - Triangle Monument History
accessdate=2007-03-24]

;June 1 1792The western counties of Virginia beyond the Appalachian Mountains were split off and admitted as the 15th state, Kentucky.

;August 2 1796
Pinckney's Treaty, also known as the Treaty of San Lorenzo, settles the northern border of West Florida as the 31st parallel. [cite web
url=http://www.yale.edu/lawweb/avalon/diplomacy/spain/sp1795.htm
title=Text of the "Treaty of Friendship, Limits, and Navigation Between Spain and The United States"
publisher=The Avalon Project at the Yale Law School
accessdate=2006-08-04]

;June 1 1796The Southwest Territory was admitted as the 16th state, Tennessee.

;May 7 1798Due to the Yazoo Land Fraud, an act was signed by President John Adams, authorizing him to appoint commissioners to negotiate with Georgia about ceding its western land. The act created Mississippi Territory in the region ceded by West Florida, corresponding to roughly the southern third of present-day Mississippi and Alabama except their panhandles, which were part of West Florida. [cite web
url=http://www.cviog.uga.edu/Projects/gainfo/tdgh-apr/apr07.htm
title=This Day in Georgia History, April 7
accessdate=2006-08-04]

1800s

;July 4 1800
Indiana Territory was formed from the western portion of Northwest Territory.cite web
url=http://www.jlindquist.com/mapsupp1.html
title=Evolution of Territories and States from the Old "Northwest Territory"
accessdate=2006-08-04] It corresponded to present-day Illinois, Indiana, northeastern Minnesota, and Wisconsin, as well as the western half of the Lower Peninsula of Michigan and all but the eastern tip of the Upper Peninsula. Northwest Territory was left with only most of Ohio and the rest of Michigan.

;July 10 1800
Connecticut ceded its Western Reserve to the federal government, which made it part of Northwest Territory, and is the northeastern part of present-day Ohio. [cite web
url=http://ech.case.edu/ech-cgi/article.pl?id=WR2
title=WESTERN RESERVE
work=Encyclopedia of Cleveland History
accessdate=2006-08-04]

;April 26 1802
Georgia finally ceded its western claims, the Yazoo Lands, to the federal government, where it became unorganized land. [cite web
url=http://www.ourgeorgiahistory.com/chronpop/3129
title=Yazoo Land Fraud
publisher=Our Georgia History
accessdate=2006-08-04] Also, on October 1 1800, the Third Treaty of San Ildefonso transferred the colony of Louisiana from Spain to France. [cite web
url=http://www.yale.edu/lawweb/avalon/ildefens.htm
title=Text of the "Treaty of San Ildefonso : October 1, 1800"
publisher=The Avalon Project at Yale Law School
accessdate=2006-08-04]

;March 1 1803The southeastern portion of Northwest Territory was admitted as the 17th state, Ohio. The remainder of Northwest Territory was transferred to Indiana Territory.

;April 30 1803The Louisiana Purchase was made, expanding the United States west of the Mississippi River. There was a dispute with West Florida over how much land east of the Mississippi River it included. [cite web
url=http://www.independent.org/publications/working_papers/article.asp?id=1478
title="Not Merely Perfidious but Ungrateful": The U.S. Takeover of West Florida
author=Robert Higgs
accessdate=2006-08-04
publisher=The Independent Institute
date=2005-03-14] The purchase extended slightly north of the modern borders, as it was defined only as the watershed of the Mississippi River. [cite web
url=http://www.archives.gov/exhibits/american_originals/louistxt.html
title=Text of the treaty for the Louisiana Purchase
publisher=United States National Archives
accessdate=2006-08-04] The purchase consisted of the whole of present-day Arkansas, Kansas, Iowa, Missouri, Nebraska, and Oklahoma, and portions of Colorado, Louisiana, Minnesota, Montana, New Mexico, North Dakota, South Dakota, Texas and Wyoming. It also included the southernmost portions of the present-day Canadian provinces of Alberta, Manitoba, and Saskatchewan.

;March 27 1804The unorganized land ceded by Georgia was added to Mississippi Territory, consisting of the whole of present-day Mississippi and Alabama, minus their panhandles which were still part of West Florida. [cite web
url=http://www.historycooperative.org/cgi-bin/justtop.cgi?act=justtop&url=http://www.historycooperative.org/journals/jah/86.1/exr_1.html
title=Exhibition Review of "1811—Year of Wonders in the Mississippi Territory."
accessdate=2006-08-04]

;October 1 1804The Louisiana Purchase was split into the District of Louisiana, which was temporarily under the authority of Indiana Territory, and the organized Orleans Territory, which corresponded to part of present-day Louisiana with a small portion of Texas. [cite web
url=http://www.yale.edu/lawweb/avalon/statutes/2us283.htm
title=Test of "An Act erecting Louisiana into two territories, and providing for the temporary government thereof."
publisher=The Avalon Project at the Yale Law School
accessdate=2006-08-04] The western border of Orleans Territory caused further conflict with New Spain, specifically over the region between the Sabine River on the west and the Arroyo Hondo (River) on the east, which became known as the Sabine Free State. This land was later confirmed as U.S. territory by the Adams-Onís Treaty of 1819.

;January 11 1805
Michigan Territory was split from Indiana Territory, including the whole of the lower peninsula of present-day Michigan but only that eastern tip of the upper peninsula which was held by the Northwest Territory after Indiana Territory had been split from it.

;July 4 1805The District of Louisiana was organized as Louisiana Territory. [cite web
url=http://rs6.loc.gov/cgi-bin/ampage?collId=llsl&fileName=002/llsl002.db&recNum=368
title=Statutes at Large, 8th Congress, 2nd Session
publisher=Library of Congress
accessdate=2006-08-04]

;March 1 1809
Illinois Territory was split from Indiana Territory. Illinois Territory included present-day Illinois, northeastern Minnesota, and Wisconsin. Indiana Territory included the present-day borders of Indiana, with its western and eastern borders continuing northward; thus, it also included the central portion of the upper peninsula of Michigan, as well as Door Peninsula of present-day Wisconsin.

1810s

;April 1810The Hawaiian islands are unified as the Kingdom of Hawaii. [cite web
url=http://hawaii-nation.org/chrono1.html
title=Historical Chronology - Key Events in the History of Hawai&okina;i Since Contact with Western Culture
work=Hawaiian Independence
accessdate=2007-08-14]

;October 27 1810By proclamation by President James Madison, the United States annexed the Baton Rouge and Mobile Districts of West Florida, declaring them part of the Louisiana Purchase. These had, 90 days earlier, declared independence as the Republic of West Florida. [cite web
url=http://fcit.usf.edu/Florida/docs/s/spanocc.htm
title=Spanish Occupation, Second
work=Floripedia
accessdate=2006-08-04]

;April 30 1812
Orleans Territory was admitted as the 18th state, Louisiana.

;May 12 1812The federal government annexed a part of West Florida, the Mobile District, to Mississippi Territory, making the territory correspond to present-day Alabama and Mississippi. [cite web
url=http://memory.loc.gov/cgi-bin/query/r?ammem/hlaw:@field(DOCID+@lit(hj008147)):
title=Journal of the House of Representatives of the United States, 1811-1813
publisher=Library of Congress
accessdate=2006-08-04]

;June 4 1812
Louisiana Territory, having the same name as a state, was renamed to Missouri Territory. [cite web
url=http://encyclopediaofarkansas.net/encyclopedia/entry-detail.aspx?entryID=2546
title=Arkansas State Boundaries
work=Encyclopedia of Arkansas
accessdate=2006-08-04]

;December 11 1816The southern portion of Indiana Territory was admitted as the 19th state, Indiana. The remainder became unorganized.

;March 3 1817
Alabama Territory was split from Mississippi Territory; both correspond to their present-day counterparts. [cite web
url=http://www.legislature.state.al.us/misc/history/constitutions/territorial/ter2.html
title=Text of "An Act To Establish A Separate Territorial Government For The Eastern Part Of The Mississippi Territory"
accessdate=2006-08-04]

;December 10 1817
Mississippi Territory was admitted as the 20th state, Mississippi.

;October 20 1818The Treaty of 1818 established the 49th parallel north west of the Lake of the Woods as the border with British-held lands, and Oregon Country was established as a shared land between the United States and United Kingdom. [cite web
url=http://www.yale.edu/lawweb/avalon/diplomacy/britain/conv1818.htm
title=Text of "Convention of 1818 between the United States and Great Britain"
publisher=The Avalon Project at Yale Law School
accessdate=2006-08-04] Oregon Country consisted of most of present-day Idaho and Oregon, all of Washington, and a portion of Montana, as well as the southern part of the Canadian province of British Columbia. The treaty transferred the Red River Basin to the United States, consisting of northwestern Minnesota, northeastern North Dakota, and the northeastern tip of South Dakota.

;December 3 1818The southern portion of Illinois Territory was admitted as the 21st state, Illinois. The remainder was reassigned to Michigan Territory.

;March 2 1819The southern part of Missouri Territory was organized as Arkansaw Territory, consisting of present-day Arkansas as well as part of Oklahoma.cite web
url=http://statoids.com/uus.html
title=States of the United States
work=Statoids
accessdate=2006-08-04] It was not officially spelled Arkansas until later.

;December 14 1819
Alabama Territory was admitted as the 22nd state, Alabama.

1820s

;March 16 1820The Maine District of Massachusetts was split off and admitted as the 23rd state, Maine, as part of the Missouri Compromise.

;July 10 1821The Adams-Onís Treaty came in to effect. It established the entirety of the border between the United States and New Spain. Under the terms of the treaty, all of Spanish Florida was sold to the United States. [cite web
url=http://www.yale.edu/lawweb/avalon/diplomacy/spain/sp1819.htm
title=Text of "Treaty of Amity, Settlement, and Limits Between the United States of America and His Catholic Majesty. 1819"
publisher=The Avalon Project at Yale Law School
accessdate=2006-08-04] The treaty transferred the rest of present-day Idaho and Oregon to Oregon Country; moved portions of present-day Colorado, Oklahoma, and Wyoming, and all of New Mexico and Texas, to New Spain; and all of Florida to the United States. The new borders intruded on Arkansaw Territory's Miller County, created on April 1 1820, which dipped below the Red River and into land now ceded to Spain. However, the remoteness of the region caused no serious conflict with Spain.cite web
url=http://www.tsha.utexas.edu/handbook/online/articles/MM/hcm91.html
title=MILLER COUNTY, ARKANSAS
publisher=The Handbook of Texas Online
accessdate=2007-11-17]

;August 10 1821The southeastern corner of Missouri Territory was admitted as the 24th state, Missouri. The remainder became unorganized. Missouri did not include its northwestern triangle at this point, that being added later in the Platte Purchase. [cite web
url=http://ioway.nativeweb.org/history/treaty1836.htm
title=TREATY WITH THE IOWA, ETC. (September 17, 1836)
publisher=The Ioway Nation
accessdate=2007-08-14]

;September 27 1821The Viceroyality of New Spain achieved independence as Mexico.

;March 30 1822
East Florida and the portion of West Florida not already part of other states were combined and organized as Florida Territory, which corresponded to present-day Florida. Around this time, the official spelling of Arkansaw Territory became Arkansas Territory.

;November 15 1824
Arkansas Territory was shrunk, the western portion becoming unorganized.cite web
url=http://www.tngenweb.org/tnletters/territories/ar-terr.html
title=Arkansas Territory 1819-1836
accessdate=2006-08-05]

;May 6 1828
Arkansas Territory was shrunk further, attaining the present-day borders of Arkansas, with the remainder again becoming unorganized, excepting the land it still claimed as Miller County.

1830s

;June 30 1834A large portion of unorganized land was added to Michigan Territory, corresponding to present-day Iowa, western Minnesota, and eastern North Dakota and South Dakota.

;March 2 1836The Republic of Texas achieved independence from Mexico, though with a large portion of the territory disputed. It had control over the eastern half of present-day Texas, and disputed the western half, as well as portions of Colorado, Kansas, New Mexico, and Wyoming. Miller County in Arkansas Territory now intruded on the borders of Texas, and the people there began to take a Texian identity, leading to both governments having representatives from the county.

;June 15 1836
Arkansas Territory was admitted as the 25th state, Arkansas. It continued to claim Miller County, with increasing irrelevance.

;July 4 1836
Wisconsin Territory was split off from Michigan Territory, consisting of present-day Wisconsin and the northeastern portion of Minnesota. As an inducement to give up its claim over the Toledo Strip to Ohio, the whole of the present-day upper peninsula was assigned to Michigan Territory, giving it the present-day borders of Michigan.

;January 26 1837
Michigan Territory was admitted as the 26th state, Michigan.

;March 28 1837The Platte Purchase added a small area of land to Missouri, giving it its present-day boundaries. [cite web
url=http://ioway.nativeweb.org/history/treaties.htm#1824
title=Ioway Cultural Institute : History - Treaties
accessdate=2006-08-04]

;July 4 1838
Iowa Territory was split off from Wisconsin Territory, consisting of present-day Iowa, western Minnesota, and eastern North Dakota and South Dakota, leaving Wisconsin Territory with northeastern Minnesota and Wisconsin.

1840s

;November 10 1842The Webster-Ashburton Treaty settled the border between the United States and lands held by the United Kingdom east of the Rocky Mountains, ending the dispute over the borders of Maine and northeastern Minnesota. [cite web
url=http://www.yale.edu/lawweb/avalon/diplomacy/britain/br-1842.htm
title=Text of "The Webster-Ashburton Treaty"
publisher=The Avalon Project at Yale Law School
accessdate=2006-08-04]

;March 3 1845
Florida Territory was admitted as the 27th state, Florida.

;December 29 1845The Republic of Texas was admitted as the 28th state, Texas. It was annexed by the United States on March 1 1845, [cite web
url=http://www.yale.edu/lawweb/avalon/texan01.htm
title=Annexation of Texas. Joint Resolution of the Congress of the United States, March 1, 1845
publisher=The Avalon Project at Yale Law School
accessdate=2007-11-20] but Texas did not agree to join the union for some time after. It brought with it all the lands of Mexico that it claimed, including all of present-day Texas, and parts of Colorado, New Mexico, Oklahoma, and Wyoming. With Texas joining the union, Arkansas finally gave up its claim on Miller County.

;June 18 1846The Oregon Treaty established the 49th parallel west of the Lake of the Woods as the continental border (so it did not include Vancouver Island) with the lands held by the United Kingdom. The sharing of Oregon Country ended, and the American portion becomes unorganized territory. [cite web
url=http://www.yale.edu/lawweb/avalon/diplomacy/britain/br-1846.htm
title=Text of "Treaty with Great Britain, in Regard to Limits Westward of the Rocky Mountains."
publisher=The Avalon Project at Yale Law School
accessdate=2006-08-04]

;December 28 1846The southeast portion of Iowa Territory was admitted as the 29th state, Iowa. The remainder became unorganized.

;March 13 1847The District of Columbia retroceded its land south of the Potomac River back to Virginia. Congress passed the retrocession act on July 9 1846, and Virginia took possession of the land on this date. [cite paper|author=Richards, Mark D.|title=The Debates over the Retrocession of the District of Columbia, 1801—2004|url=http://www.dcvote.org/pdfs/mdrretro062004.pdf|format=PDF|accessdate=2007-03-23]

;February 2 1848The Treaty of Guadalupe Hidalgo, ending the Mexican-American War, granted a large area of land to the United States from Mexico. [cite web
url=http://www.yale.edu/lawweb/avalon/diplomacy/mexico/guadhida.htm
title=Text of "Treaty of Guadalupe Hidalgo"
publisher=The Avalon Project at Yale Law School
accessdate=2006-08-04] It consisted of all of present-day California, Nevada, and Utah, most of Arizona, and portions of Colorado, New Mexico, and Wyoming.

;May 29 1848The southeastern portion of Wisconsin Territory was admitted as the 30th state, Wisconsin. The remainder became unorganized.

;August 14 1848
Oregon Territory was organized, including present-day Idaho, northwestern Montana, Oregon, Washington, and western Wyoming. [cite web
url=http://lcweb2.loc.gov/ammem/today/aug14.html
title=Today in History: August 14
publisher=Library of Congress
accessdate=2006-08-04]

;March 3 1849
Minnesota Territory was organized, consisting of present-day Minnesota, and eastern portions of North Dakota and South Dakota. [cite web
url=http://www.sos.state.mn.us/student/act1849.pdf
title=An Act to Establish the Territorial Government of Minnesota
accessdate=2006-08-04
format=PDF
pages=4]

1850s

;September 9 1850The Mexican Cession was divided as part of the Compromise of 1850. The western portion was admitted as the 31st state, California. The rest was organized as Utah Territory and New Mexico Territory. Both territories also included land ceded to the federal government by Texas in exchange for taking on its debts; a portion of Texas and the Mexican Cession became unorganized land. [cite web
url=http://ourdocuments.gov/print_friendly.php?flash=false&page=transcript&doc=27&title=Transcript+of+Compromise+of+1850+(1850)
title=Transcript of Compromise of 1850
accessdate=2006-08-04] A peculiarity appeared at this time, when a small strip of land north of Texas was not officially assigned by any state or territory; this came to be called the Neutral Strip or "No Man's Land", which corresponds to the present-day panhandle of Oklahoma. [cite web
url=http://www.ok-history.mus.ok.us/enc/nomansland.htm
title=NO MAN'S LAND
accessdate=2006-08-04] New Mexico Territory consisted of most of present-day Arizona and New Mexico, as well as a southern portion of Colorado and the southern tip of Nevada. Utah Territory consisted of present-day Utah, most of Nevada, and portions of Colorado and Wyoming.

;March 2 1853
Washington Territory was split from Oregon Territory, consisting of present-day Washington, northern Idaho, and the western tip of Montana, leaving Oregon Territory with all of Oregon, southern Idaho and a portion of Wyoming. [cite web
url=http://www.washingtonhistory.org/wshs/columbia/articles/0303-a4.htm
title=The Creation of Washington Territory
publisher=Columbia Magazine
accessdate=2006-08-04]

;December 30 1853The Gadsden Purchase added some land to New Mexico Territory, corresponding to the southernmost areas of present-day Arizona and New Mexico. [cite web
url=http://www.yale.edu/lawweb/avalon/diplomacy/mexico/mx1853.htm
title=Text of "Gadsden Purchase Treaty"
publisher=The Avalon Project at Yale Law School
accessdate=2006-08-04]

;May 30 1854
Kansas Territory and Nebraska Territory were organized; the remaining unorganized land colloquially became known as Indian Territory. [cite web
url=http://www.yale.edu/lawweb/avalon/kanneb.htm
title=Text of "An Act to Organize the Territories of Nebraska and Kansas."
publisher=The Avalon Project at Yale Law School
accessdate=2006-08-04] Kansas Territory consisted of present-day Kansas and eastern Colorado. Nebraska Territory consisted of present-day Nebraska, and parts of Colorado, Montana, North Dakota, South Dakota, and Wyoming. Indian Territory corresponds to eastern Oklahoma.

;May 11 1858The eastern portion of Minnesota Territory was admitted as the 32nd state, Minnesota. The remainder became unorganized.

;February 14 1859The western portion of Oregon Territory was admitted as the 33rd state, Oregon. The remainder was assigned to Washington Territory. [cite web
url=http://www.oregonriverrights.com/admissions_act.htm
title=Text of "Act of Congress Admitting Oregon into Union"
accessdate=2006-08-04]

1860s

;February 8 1860Texas began claiming Greer County, Texas, controlled at that time by the federal government as unorganized territory, and now in present-day Oklahoma. [cite web
url=http://www.tsha.utexas.edu/handbook/online/articles/GG/hcg81.html
title=GREER COUNTY
work=The Handbook of Texas Online
accessdate 2006-08-04]

;January 29 1861The eastern portion of Kansas Territory was admitted as the 34th state, Kansas. A peculiarity arose for the western portion. It was added to Colorado Territory on February 28 1861; however, for the month between statehood for Kansas and the Colorado Territory being formed, it appears to have had no official status.cite web
url=http://www.colorado.gov/dpa/doit/archives/arcgov.html
title=Colorado Government
accessdate=2006-08-04]

;February 4 1861The Confederate States of America (CSA) was formed. The Southern states seceded at different dates and joined the CSA at different dates; to simplify the map, only the final form of the CSA is shown here. There were rebel governments as well as Union governments in Kentucky and Missouri, and the CSA had full control over Indian Territory. To view a detailed animated map depicting the various state secessions see .

;February 28 1861
Colorado Territory was organized, with land from Utah, New Mexico, and Nebraska Territories, as well as the land left over from Kansas Territory; it corresponded already to present-day Colorado.

;March 2 1861
Dakota Territory was split from Nebraska Territory, and included the unorganized land left over from Minnesota Territory. Dakota Territory consisted of both present-day North and South Dakota, as well as most of Montana and northern Wyoming. Nebraska Territory consisted of all of Nebraska and southeastern Wyoming. [cite web
url=http://www.state.nd.us/hist/chrono.htm
title=North Dakota Chronology
accessdate=2006-08-04] Nevada Territory was split from Utah Territory, corresponding to northwestern present-day Nevada; the eastern border was the 39th meridian west of Washington, D.C. [cite web
url=http://www.nevadaobserver.com/Reading%20Room%20Documents/Nevada%20-%20Organizing%20the%20Territory%20(1912).htm
title=Organizing the Territory
publisher=Nevada Observer
accessdate=2006-08-04]

;August 1 1861The Confederacy established Arizona Territory (CSA) in the southern half of the Union's New Mexico Territory. It would be organized on February 14 1862. It corresponded to the southern halves of present-day Arizona and New Mexico. [cite web
url=http://members.tripod.com/~azrebel/page10.html
title=THE FORGOTTEN LEGACY: A Short History of the Confederate Territory of Arizona
accessdate=2006-08-04]

;July 14 1862Due to its nature as a mining and grazing area, land started to be added to Nevada Territory to accommodate these activities. Its eastern border was moved eastward from the 39th meridian west from Washington, to the 38th meridian west from Washington, transferring the land from Utah Territory.cite web
url=http://www.nevadaobserver.com/Reading%20Room%20Documents/Nevada%20-%20Adjustment%20of%20the%20Boundaries%20(1912).htm
title=The History of Nevada: The Adjustment of the Boundaries of Nevada
accessdate=2006-08-04]

;February 24 1863The Union created its own Arizona Territory, splitting it off from New Mexico Territory, making both territories correspond to their present-day states, except for Arizona Territory including the southern tip of present-day Nevada. [cite web
url=http://lcweb2.loc.gov/cgi-bin/ampage?collId=llhb&fileName=037/llhb037.db&recNum=1985
title=Bills and Resolutions, House of Representatives, 37th Congress, 2nd Session
publisher=Library of Congress
accessdate=2006-08-04]

;March 4 1863
Idaho Territory was created from portions of Washington, Dakota, and Nebraska Territories, consisting of present-day Idaho, Montana, and most of Wyoming. Nebraska and Washington Territories were left corresponding to their present-day counterparts. [cite web
url=http://www.cr.nps.gov/history/online_books/glac/adhi1.htm
title=Glacier National Park - Administrative History
accessdate=2006-08-04]

;June 20 1863Several counties of northwestern Virginia who didn't want to be part of the Confederacy split off and were admitted as the 35th state, West Virginia.

;May 26 1864
Montana Territory was split from Idaho Territory, which also had some land transferred to Dakota Territory. Montana Territory corresponded to present-day Montana, Idaho Territory consisted of Idaho and western Wyoming, and Dakota Territory included both North and South Dakota, and most of Wyoming. [cite web
url=http://memory.loc.gov/ammem/today/may26.html
title=Today in History: May 26
publisher=Library of Congress
accessdate=2006-08-04]

;October 31 1864
Nevada Territory was admitted as the 36th state, Nevada; it was a bit smaller than it is today, lacking area in both the east and south.

;April 9 1865The Confederate States of America surrendered. The process of Reconstruction and readmission to the union would take several years; to simplify the map, they are shown as already readmitted. To view a detailed animated map depicting the various state readmission during Reconstruction see .

;May 5 1866
Nevada's eastern border was moved from the 38th meridian west from Washington, to the 37th meridian west from Washington, transferring land to it from Utah Territory.

;January 18 1867The northwestern corner of Arizona Territory was transferred to the state of Nevada, giving it its present-day borders. [cite web
url=http://dcnr.nv.gov/markers/mark_57.htm
title=Old Boundary, (Nevada's Southern Boundary 1861-1867), Nevada Historical Marker 57
publisher=Nevada Division of Water Planning
accessdate=2006-08-10]

;March 1 1867
Nebraska Territory was admitted as the 37th state, Nebraska.

;October 11 1867The United States purchased Alaska from Russia; it was designated the Department of Alaska, and corresponds, except for a boundary dispute, to present-day Alaska. [cite web
url=http://www.yale.edu/lawweb/avalon/diplomacy/russia/treatywi.htm
title=Text of "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"
publisher=The Avalon Project at Yale Law School
accessdate=2006-08-04]

;July 25 1868
Wyoming Territory was formed from portions of Dakota, Idaho, and Utah Territories, corresponding to the present-day borders of Wyoming. [cite web
url=http://enzi.senate.gov/public/index.cfm?FuseAction=AboutWyoming.WyomingFacts
title=Wyoming Facts
accessdate=2006-08-04]

1870s

;October 21 1872
San Juan Islands awarded to the U.S., formally ending the Pig War with the Britain.

;August 1 1876
Colorado Territory was admitted as the 38th state, Colorado.

1880s

;March 28 1882The part of Dakota Territory south of 43° north and north of the Keya Paha and Niobrara Rivers was transferred to Nebraska. [cite web
url=http://www.rootsweb.com/~neresour/OLLibrary/MWHNE/mwhne388.htm
title=History of Nebraska
accessdate=2007-08-02]

;May 17 1884The Department of Alaska, previously under the direct control of the federal government and the military, was redesignated the District of Alaska, forming a local government. [cite web
url=http://www.alaskool.org/projects/native_gov/legislation/organic_act/organic_act_1884.htm
title=Text of "An Act Providing a Civil Government for Alaska"
accessdate=2006-08-04]

;November 2 1889
Dakota Territory was split in two, and it was admitted as the 39th state, North Dakota, and 40th state, South Dakota.

;November 8 1889
Montana Territory was admitted as the 41st state, Montana.

;November 11 1889
Washington Territory was admitted as the 42nd state, Washington.

1890s

;May 2 1890
Oklahoma Territory was organized from the western portion of Indian Territory, and included the Neutral Strip, and corresponded to the western half of present-day Oklahoma. [cite web
url=http://www.odl.state.ok.us/oar/resources/territorialgov.htm
title=Papers of the Territorial Governors
accessdate=2006-08-04]

;July 3 1890
Idaho Territory was admitted as the 43rd state, Idaho.

;July 10 1890
Wyoming Territory was admitted as the 44th state, Wyoming.

;July 4 1894The Kingdom of Hawaii became the Republic of Hawaii.cite web
url=http://www.hawaii-nation.org/chrono1.html
title=Historical Chronology, Key Events in the History of Hawai`i Since Contact with Western Culture
accessdate=2006-08-04]

;January 4 1896
Utah Territory was admitted as the 45th state, Utah.

;May 4 1896A Supreme Court ruling officially assigns Greer County to Oklahoma Territory. [cite web
url=http://digital.library.okstate.edu/chronicles/v012/v012p145.html
title=Chronicles of Oklahoma, Volume 12, No. 2, June, 1934: GREER COUNTY
accessdate=2006-08-04]

;August 12 1898The Republic of Hawaii was annexed by the United States.

20th century

;June 14 1900The annexed Hawaiian islands were organized as the Territory of Hawaii, and corresponded, except for including Palmyra Atoll, to the present-day state of Hawaii.

;October 20 1903The Alaska boundary dispute is resolved by arbitration, generally favoring the American claim.

;November 16 1907
Oklahoma Territory and Indian Territory were combined and admitted as the 46th state, Oklahoma.

;January 6 1912
New Mexico Territory was admitted as the 47th state, New Mexico.

;February 14 1912
Arizona Territory was admitted as the 48th state, Arizona.

;August 24 1912The District of Alaska was organized as Alaska Territory. [cite web
url=http://www.alaskahistoricalsociety.org/calendar%20August.htm
title=This Month in Alaska History
accessdate=2006-08-04]

;March 28 1921The dispute over a square mile between Delaware and Pennsylvania, The Wedge, is finally resolved in favor of Delaware. [cite web|url=http://ucblibraries.colorado.edu/govpubs/conference/handouts/Erie/Erie.ppt |title=The Erie Triangle |format=PPT |accessdate=2007-08-01]

;January 3 1959
Alaska Territory was admitted as the 49th state, Alaska

;August 21 1959
Hawaii Territory was admitted as the 50th state, Hawaii, resulting in the present-day situation of the United States. The statehood act specifically excluded Palmyra Atoll from the new state; it thus became unorganized land. Since it had been incorporated as part of the Hawaii Territory, Palmyra Atoll became the only incorporated territory left in the United States.

References

ee also

*Geography of the United States
*History of the United States
*List of U.S. states by date of statehood
*United States territorial acquisitions
*United States territory
*U.S. state

External links

* [http://statoids.com/uus.html States of the United States] from Statoids.com.
* [http://www.usmint.gov/mint_programs/50sq_program/index.cfm?flash=yes&action=schedule The 50 State Quarters Program] at the United States Mint, listing dates of statehood.
* [http://www.doi.gov/oia/Islandpages/acquisition_process.htm Acquisition Process of Insular Areas] - lists all insular areas.
* [http://www.internationalboundarycommission.org/ibcmenup.htm International Boundary Commission] between Canada and the U.S.