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Basic Information

2010 Census Population: 37,253,956 (1st)
Land Area: 155,779.2 square miles (3rd)
Density: 239.1 persons per square mile (11th)
Capital: Sacramento
Became a State: September 9, 1850 (31st)
Bordering States: Arizona, Nevada, Oregon
International Border: Mexico
Abbreviation: CA
ANSI Code: 06


The United States acquired the area of California from Mexico in 1848, with generally the same boundary as the present state. The area of California was never organized as a territory, but was administered from 1848 to statehood by a federal military authority. California was admitted to the Union on September 9, 1850, as the 31st state.

Census data for California are available beginning with the 1850 census; however, the data for 1850 are incomplete because the questionnaires from Contra Costa and Santa Clara Counties were lost and those for San Francisco County were destroyed by fire. Some missing 1850 data have been supplanted by information obtained from a state census in 1852.

Data for the legally established state of California are available beginning with the 1850 census.

About the Geographic Areas


California has 108 federally recognized American Indian areas.  There are 104 reservations; 28 with off-reservation trust land in the state.  Two are trust lands only. The remaining two are tribal designated statistical areas (TDSAs). 


California has 26 metropolitan statistical areas, 9 micropolitan statistical areas, 4 combined statistical areas, and 4 metropolitan divisions.


There are 58 counties in California.  The city and county of San Francisco have consolidated functions and is classified as a municipal government that operates primarily as a city.  All other counties are each governed by a board of supervisors. 


There are 397 county subdivisions in California. 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 in California for the 1960 census.  Prior to 1960, the minor civil divisions used in the census included election precincts, judicial townships, supervisor’s districts, and one American Indian reservation (in 1870).


California has 1,523 places; 480 incorporated places and 1,043 census designated places (CDPs).  The incorporated places consist of 459 cities and 21 towns.  In California an incorporated place can legally exist only in a single county.


California has 8,057 census tracts, 23,212 block groups, and 710,145 blocks.


For the 111th Congress (January 2009-January 2011), California had 53 congressional districts.  For the 113th Congress (January 2013-January 2015), California continues to have 53 congressional districts as a result of the reapportionment based on the 2010 Census.


California has 548 elementary school districts, 104 secondary school districts, and 335 unified school districts. 


There are 40 state senate districts and 80 assembly districts in California.


California has 211 urban areas; 59 urbanized areas and 152 urban clusters.


There are 1,769 ZIP Code tabulation areas (ZCTAs) in California.

Centers of Population

Year North Latitude West Longitude
20106 35° 27′ 49″ 119° 19′ 31″
20006 35° 27′ 31″ 119° 21′ 19″
19905 35° 26′ 35″ 119° 21′ 44″
19804 35° 28′ 29″ 119° 26′ 17″
19703 35° 28′ 03″ 119° 28′ 31″
19603 35° 30′ 13″ 119° 31′ 13″
19503 35° 44′ 46″ 119° 39′ 01″
19402 35° 38′ 27″ 119° 35′ 18″
19302 35° 43′ 12″ 119° 41′ 06″
19201 36° 20′ 23″ 120° 10′ 54″
19101 36° 42′ 29″ 120° 31′ 23″
19001 37° 14′ 26″ 120° 53′ 11″
18901 37° 25′ 35″ 121° 02′ 20″
18801 37° 55′ 55″ 121° 27′ 42″

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

Most Populous, Largest, and Dense Areas

Population Land Area
(square miles)
Population Density
(Persons per square mile)

Name Population Name Area Name Density
County Los Angeles County 9,818,605 San Bernardino County 20,056.94 San Francisco County 17,179.2

— Inc Place Los Angeles city 3,792,621 Los Angeles city 468.67 Maywood city 23,247.5
— CDP East Los Angeles CDP 126,496 Lucerne Valley CDP 105.59 Walnut Park CDP 21,352.0

List of Entities

See the Gazetteer Files for a list of geographic entities. See the Metropolitan and Micropolitan Statistical Areas page for a list of metropolitan and micropolitan statistical areas and related statistical areas.


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