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Population of Counties in California (2024)

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2024 Population
Growth Since 2020
Area (mi²)
Density (/mi²)
Los Angeles County9,606,925-3.86%1.6K2,366Los Angeles County location
San Diego County3,262,770-0.99%1.6K775San Diego County location
Orange County3,121,138-2.03%3063,936Orange County location
Riverside County2,510,6433.62%2.8K348Riverside County location
San Bernardino County2,196,3140.59%7.7K109San Bernardino County location
Santa Clara County1,876,849-2.81%4981,454Santa Clara County location
Alameda County1,616,117-3.83%2842,193Alameda County location
Sacramento County1,584,196-0.15%3721,642Sacramento County location
Contra Costa County1,153,031-1.12%2771,608Contra Costa County location
Fresno County1,018,9650.93%2.3K171Fresno County location
Kern County910,8890.55%3.1K112Kern County location
Ventura County826,309-2.02%711449Ventura County location
San Francisco County810,202-6.93%1817,238San Francisco County location
San Joaquin County807,6373.46%537580San Joaquin County location
San Mateo County723,777-5.08%1731,612San Mateo County location
Stanislaus County551,634-0.29%577369Stanislaus County location
Tulare County481,0521.51%1.9K100Tulare County location
Sonoma County480,955-1.5%608305Sonoma County location
Solano County449,551-0.7%317547Solano County location
Santa Barbara County438,599-2.19%1.1K160Santa Barbara County location
Placer County429,0485.7%543305Placer County location
Monterey County428,562-2.23%1.3K131Monterey County location
Merced County293,6304.19%748152Merced County location
San Luis Obispo County281,232-0.23%1.3K85San Luis Obispo County location
Santa Cruz County258,854-4.3%172582Santa Cruz County location
Marin County252,660-3.31%201486Marin County location
Yolo County219,0701.28%391216Yolo County location
Butte County206,975-1.51%631127Butte County location
El Dorado County191,6430.21%659112El Dorado County location
Shasta County179,795-1.21%1.5K48Shasta County location
Imperial County179,174-0.24%1.6K43Imperial County location
Madera County165,3875.78%82577Madera County location
Kings County152,377-0.31%537110Kings County location
Humboldt County133,026-2.37%1.4K37Humboldt County location
Napa County132,062-3.93%290176Napa County location
Nevada County101,673-0.58%370106Nevada County location
Sutter County97,327-2.16%233161Sutter County location
Mendocino County88,209-3.46%1.4K25Mendocino County location
Yuba County87,0916.26%244138Yuba County location
San Benito County68,7076.47%53649San Benito County location
Lake County67,584-0.9%48454Lake County location
Tehama County64,493-1.82%1.1K22Tehama County location
Tuolumne County53,821-2.81%85724Tuolumne County location
Calaveras County46,5742.7%39446Calaveras County location
Amador County42,1293.96%23071Amador County location
Siskiyou County42,024-4.48%2.4K7Siskiyou County location
Glenn County27,898-3.48%50721Glenn County location
Lassen County27,702-14.28%1.8K6Lassen County location
Del Norte County26,066-5.57%38826Del Norte County location
Colusa County22,1651.38%44419Colusa County location
Plumas County18,819-4.69%9857Plumas County location
Inyo County18,312-3.56%3.9K2Inyo County location
Mariposa County16,785-1.95%55912Mariposa County location
Trinity County15,562-3.29%1.2K5Trinity County location
Mono County13,130-0.74%1.2K4Mono County location
Modoc County8,381-3.46%1.5K2Modoc County location
Sierra County3,178-1.46%3683Sierra County location
Alpine County1,092-9.38%2851Alpine County location
showing: 58 rows

There are 58 counties in California. Not surprisingly, California's Los Angeles County is the largest county in the state, as well as the nation, with a huge population of 10,150,558 that continues to grow – the most recent census shows that its population has increased by 3.32% since the last census. A number of other Californian counties also boast large populations, although they look small in comparison to Los Angeles County. San Diego County has a population of 3,337,685 and a growth rate of 7.8%, while neighboring Orange County has 3,190,400 residents and a growth rate of 6%.

The smallest county in California is Alpine County, with its population of just 1,120. This total represents a decrease of 4.7% since the last census count performed in 2010. Sierra County and Modoc County follow, with populations of 2,999 and 8,859, respectively, and negative growth rates of 7.4% and 8.5%. Many other counties have fewer than fifty thousand residents, such as Trinity County (12,839), Del Norte County (27,450), and Siskiyou County (43,511) – each of these counties also show negative growth rates. However, one smaller county, San Benito County (59,335) has increased its population by an impressive 6.85% since the last census.

Alameda County, with its sizeable population of 1,653,236, has shown the largest population growth, with a substantial increase of 10.1% – this can perhaps be attributed to its proximity to San Francisco. Indeed, San Francisco County also has a substantial population growth of 8.73% and 876,103 residents. Lassen County has the highest negative growth, with its 31,000 residents representing a significant decrease of 10.7%.

Lists of Counties in all States

  1. California State Demographics
  2. California's Population
  3. US Census State Population Estimates - Most recent state estimates from the Census Bureau's Population Estimates Program
  4. US Census County Population Estimates - Most recent county estimates from the Census Bureau's Population Estimates Program
  5. American Community Survey (2009 - 2013)
  6. Census QuickFacts
  7. Historical Populations of States and Counties (1790 - 1990)