The U.S. state of California is divided into 58 counties. Counties are responsible for local services and law enforcement for areas within their borders that are not within incorporated cities, as well as providing local-level courts.
On January 4, 1850, the California constitutional committee recommended the formation of 18 counties. They were Benicia, Butte, Fremont, Los Angeles, Mariposa, Monterey, Mount Diablo, Oro, Redding, Sacramento, San Diego, San Francisco, San Joaquin, San Jose, San Luis Obispo, Santa Barbara, Sonoma, and Sutter. On April 22, the counties of Branciforte, Calaveras, Coloma, Colusi, Marin, Mendocino, Napa, Trinity, and Yuba were added. Benicia was renamed Solano, Coloma to El Dorado, Fremont to Yola, Mt. Diablo to Contra Costa, San Jose to Santa Clara, Oro to Tuolumne, and Redding to Shasta. One of the first state legislative acts regarding counties was to rename Branciforte County to Santa Cruz, Colusi to Colusa, and Yola to Yolo.
The present number of counties was achieved over time by subdivision of many of the larger counties into smaller ones. The original counties formed in 1850 are marked in the 'created' column with an asterisk (*).
List of 58 counties in the U.S. state of California (the links in the column FIPS County Code are to the Census Bureau Info page for that county):
One of the original counties. Part of the county's territory went to Tulare County in 1852, Merced in 1855, Fresno in 1856 and Mono in 1861. Mariposa County was the largest of the state's original counties, but territory that was once part of Mariposa is now part of 12 other counties -- Fresno, Inyo, Kern, Kings, Los Angeles, Madera, Merced, Mono, San Benito, San Bernardino, San Luis Obispo, and Tulare.
from parts of Los Angeles County. Part of the county's territory went to Riverside in 1893
Map of San Bernadino, San Diego, San Francisco, San Joaquin, San Luis Obispo, San Mateo, Santa Barbara, Santa Clara and Santa Cruz counties in California
*Klamath County was created in 1851 from the northern half of Trinity County, but in 1874 it was divided between Humboldt and Siskiyou counties. Part of the county's territory went to Del Norte in 1857 *Pautah County was created in 1852 out of territory which, the state of California assumed, was to be ceded to it by the United States Congress from territory in what is now the state of Nevada. When the cession never occurred, the state legislature officially abolished the never-created county in 1859.
