The United States acquired the area of Oklahoma from France as part of the Louisiana Purchase in 1803. Part of present-day Oklahoma, which had been included in Arkansas Territory, was ceded to Spain by conclusion of a treaty in 1819; the ceded area was reacquired as part of the annexation of Texas in 1845. The area of Oklahoma was part of unorganized territory designated as Indian Country or Indian Territory on June 20, 1834, although this conflicted with territory already included within Missouri Territory. Oklahoma Territory was organized on May 2, 1890, from the western part of Indian Territory and the Public Land Strip (the panhandle, which was sold to the United States by Texas), and resulted in the territory being in two pieces. The territory was enlarged with the addition of the Cherokee Outlet, which joined Oklahoma Territory into a single area. The Supreme Court affirmed the claim of Oklahoma to the Greer County area in southwest Oklahoma in 1896. Oklahoma Territory and the remaining Indian Territory were combined, and Oklahoma was admitted to the Union on November 16, 1907, as the 46^th state, with generally the same boundary as the present state. A boundary dispute with Texas was settled in 1930, deleting a narrow strip of territory from Oklahoma.

Census data are available for Oklahoma beginning with the 1890 census. The 1890 and 1900 census populations reported for Oklahoma include the population for Indian Territory. The population of Oklahoma Territory as legally established was 398,331 in 1900 and 78,475 in 1890. The population of Indian Territory as legally established was 392,060 in 1900 and 180,182 in 1890. The Census Bureau conducted a special census of the Oklahoma and Indian territories on July 7, 1907. The population of the entire area was 1,414,177.

Data for the legally established state of Oklahoma are available beginning with the 1910 census.

AMERICAN INDIAN AREAS

Oklahoma has 1 federally recognized American Indian area reservation, 25 Oklahoma tribal statistical areas (OTSAs), and 4 joint-use OTSAs.  The OTSAs represent the former reservations.

METROPOLITAN AND MICROPOLITAN STATISTICAL AREAS AND RELATED STATISTICAL AREAS

Oklahoma has 4 metropolitan statistical areas, 18 micropolitan statistical areas, and 2 combined statistical areas.

COUNTIES

There are 77 counties in Oklahoma.  All counties are functioning governments, each governed by a board of county commissioners.

COUNTY SUBDIVISIONS

There are 305 county subdivisions in Oklahoma. They are all census county divisions (CCDs), which are delineated for statistical purposes, have no legal function, and are not governmental units.  CCDs were first established for the 1970 census.  Prior to 1970, the minor civil divisions used in the census include townships (most of which were non-functioning, administrative areas) and election precincts.

PLACES

Oklahoma has 733 places, 597 incorporated places and 136 census designated places (CDPs).  The incorporated places consist of 164 cities and 433 towns.  There are four inactive towns - Erin Springs, New Woodville, Oak Grove, and Smithville.  Cities have a minimum population of 1,000 and villages have a population less than 1,000. 

CENSUS TRACTS/BLOCK GROUPS/BLOCKS

Oklahoma has 1,046 census tracts, 2,965 block groups, and 269,118 census blocks.

CONGRESSIONAL DISTRICTS

For the 111^th Congress (January 2009-January 2011), Oklahoma had five congressional districts.  For the 113^th Congress (January 2013-January 2015), Oklahoma continues to have five congressional districts as a result of reapportionment based on the 2010 Census.

SCHOOL DISTRICTS

Oklahoma has 106 elementary school districts and 426 unified school districts.

STATE LEGISLATIVE DISTRICTS

There are 48 state senate districts and 101 state house districts in Oklahoma.

URBAN AREAS

Oklahoma has 86 urban areas; 5 urbanized areas and 81 urban clusters.

ZIP CODE TABULATION AREAS

There are 649 ZIP Code tabulation areas (ZCTAs) in Oklahoma. 

¹  Source:  U.S. Department of Commerce, Bureau of the Census, Fourteenth Census of the United States, 1923
²  Source:  U.S. Census Bureau, recomputation for historical county level data which relied upon aggregate county level population data with an estimated county centroid resulting in a possible error of up to one mile.
³  Source:  U.S. Department of Commerce, Bureau of the Census, Centers of Population for States and Counties, 1974
⁴  Source:  U.S. Census Bureau, Geography Division, recomputation from archived national block group/enumeration area data resulting in a possible error of up to 1,000 feet.
⁵  Source:  U.S. Census Bureau, Geography Division, recomputation from archived national block group data resulting in a possible error of up to 1,000 feet.
⁶  Source:  U.S. Census Bureau, computation from national block-level data