The United States acquired most of the area of Arizona from Mexico in 1848. The United States acquired additional area, comprising the southern part of Arizona, from Mexico in 1853 as part of the Gadsden Purchase. Arizona Territory was organized from the western part of New Mexico Territory on February 24, 1863. Part of Arizona Territory north and west of the Colorado River was added to the state of Nevada in 1866, resulting in generally the same boundary as the present state of Arizona.
Although the territory had not yet been legally established, census data are available for Arizona beginning with the 1860 census. For an explanation of the revision to the 1860 population of Arizona, see Richard L. Forstall, Population of States and Counties of the United States: 1790-1990, Washington, DC: U.S. Government Printing Office, 1996, page 14.
Data for the legally established state of Arizona are available beginning with the 1920 census.
See: Geographic Terms & Concepts
Counties & County Equivalents
There are 15 counties in Arizona. Each county is governed by a board of supervisors.
Interactive Map of Arizona Counties | Static Overview Map of Arizona Counties
There are 80 county subdivisions in Arizona. They are all census county divisions (CCDs), which are delineated for statistical purposes, have no legal function, and are not governmental units.
Places (Incorporated Cities, Towns & Census Designated Places)
Arizona has 451 places; 90 incorporated places and 361 census designated places (CDPs). The incorporated places consist of 45 cities and 45 towns. The minimum population threshold required for incorporation is 1,500.
Alphabetical List of Cities, Towns, CDPs and Other Populated Places
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q, R | S | T | U, V | W, X, Y, Z
Arizona Civil Features
Arizona Civil Features: Political Subdivisions, Native Areas, Land Grants, etc. - sorted by Census Class Codes.
Metropolitan and Micropolitan Stastical Areas
There are 7 Metropolitan and 4 Micropolitan Statistical Areas in Arizona. AZ Metopolitan & Micropolitan Areas
Arizona ZIP Code Tabulation Areas
There are 408 ZIP Code tabulation areas (ZCTAs) in Arizona. View Arizona ZIP Codes and ZIP Code Maps.
Arizona has 104 elementary school districts, 15 secondary school districts, and 99 unified school districts. View Arizona Public and Private Schools.
Arizona has 9 congressional districts. An interactive map shows the contact information for each Representative as well as the boundaries for each Arizona district. View Map of Arizona Congressional Districts.
State Legislative Districts
There are 30 state senate districts and 30 state house districts in Arizona.
American Indian Areas
Arizona has 21 federally recognized American Indian reservations; 4 with associated off-reservation trust lands in the state.