The United States acquired the area of Iowa from France in 1803 as part of the Louisiana Purchase. Iowa Territory was organized on June 12, 1838, from part of Wisconsin Territory; it included all of present-day Iowa, the eastern part of North Dakota and South Dakota, and the western part of Minnesota. Iowa was admitted to the Union on December 28, 1846, as the 29^th state with generally the same boundary as the present state. The remaining part of the territory was unattached until the organization of Minnesota Territory in 1849. Nebraska and Iowa have made periodic adjustments to their boundary as the Missouri River has changed its course.

Census data for Iowa are available beginning with the 1840 census. The 1840 population includes the portion of Iowa Territory in present-day Minnesota west of the Mississippi River and a line drawn from its source northward to the Canadian boundary.

American Indian Areas

Iowa has four federally recognized American Indian areas. There are three reservations and one trust land.

Metropolitan And Micropolitan Statistical Areas And Related Statistical Areas

Iowa has 9 metropolitan statistical areas, 15 micropolitan statistical areas, and 4 combined statistical areas.

Counties

There are 99 counties in Iowa.  All counties in Iowa are functioning governmental units; each governed by a county board of supervisors.

County Subdivisions

There are 1,661 county subdivisions in Iowa known as minor civil divisions (MCDs). There are 1,598 townships. There are 59 cities that are independent of any MCD and one city (Tabor) that is partially independent of any MCD creating 62 county subdivisions. There is also one unorganized territory (reservoir property in Polk County).

Iowa township officials have minimal powers and are under the fiscal authority of the county.  These townships, by agreement with the state, are classified as nonfunctioning MCDs by the Census Bureau.  The governing body for each township is the board of township trustees.

Places

Iowa has 1,009 places; 947 incorporated places and 62 census designated places (CDPs). The incorporated places are all cities.  There are 887 incorporated places that are dependent within county subdivisions.  Fifty-two cities are legally coextensive with county subdivisions, eight cities are independent of any township, and one city (Tabor) is independent of any township in Fremont County and dependent in Mills County.

Census Tracts/Block Groups/Blocks

Iowa has 825 census tracts, 2,630 block groups, and 216,007 census blocks.

Congressional Districts

For the 111^th Congress (January 2011- January 2013) Iowa had five congressional districts.  For the 113^th Congress (January 2013-January 2015), Iowa has four congressional districts as a result of reapportionment based on the 2010 Census.

School Districts

Iowa has 364 unified school districts.

State Legislative Districts

There are 50 state senate districts and 100 state house districts in Iowa.

Urban Areas

Iowa has 99 urban areas; 9 urbanized areas and 90 urban clusters.

Zip Code Tabulation Areas

There are 935 ZIP Code tabulation areas (ZCTAs) in Iowa.

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