California Population By County in 2021 (ACS-5Yrs)
Updated on February 28, 2025.
Based on the US Census ACS-5Yrs estimates, in 2021, the total population of California was 39.46M. Among all California counties, Los Angeles was the most populated county (10.02M), followed by San Diego (3.30M), and then Orange (3.18M).
On the other hand, the least populated counties were: Alpine (1.34K), Sierra (3.08K), and Modoc (8.72K).
The chart and table below shows the population of each county and the percentage of California population in each county.
You can see similar information for other states and by state for the United States.
Related Topics: California ACS-5Yrs Estimates, 2021 Topic List.
Data Source: US Census - ACS 5-Year Estimates, 2021 Census.
California Population By County in 2021
California Population By County in 2021
Items per page:
25
0 of 0
| County | Population | % of State Population |
|---|---|---|
| Alameda | 1673133 | 4.24 |
| Alpine | 1344 | 0.00 |
| Amador | 40095 | 0.10 |
| Butte | 217884 | 0.55 |
| Calaveras | 45349 | 0.12 |
| Colusa | 21780 | 0.06 |
| Contra Costa | 1161643 | 2.94 |
| Del Norte | 27655 | 0.07 |
| El Dorado | 190568 | 0.48 |
| Fresno | 1003150 | 2.54 |
| Glenn | 28675 | 0.07 |
| Humboldt | 137014 | 0.35 |
| Imperial | 180051 | 0.46 |
| Inyo | 18804 | 0.05 |
| Kern | 905644 | 2.30 |
| Kings | 151887 | 0.39 |
| Lake | 67749 | 0.17 |
| Lassen | 32949 | 0.08 |
| Los Angeles | 10019635 | 25.40 |
| Madera | 156304 | 0.40 |
| Marin | 262387 | 0.67 |
| Mariposa | 17225 | 0.04 |
| Mendocino | 91534 | 0.23 |
| Merced | 279150 | 0.71 |
| Modoc | 8723 | 0.02 |
| Mono | 13291 | 0.03 |
| Monterey | 438953 | 1.11 |
| Napa | 138795 | 0.35 |
| Nevada | 102090 | 0.26 |
| Orange | 3182923 | 8.07 |
| Placer | 400330 | 1.01 |
| Plumas | 19631 | 0.05 |
| Riverside | 2409331 | 6.11 |
| Sacramento | 1571767 | 3.98 |
| San Benito | 63329 | 0.16 |
| San Bernardino | 2171071 | 5.50 |
| San Diego | 3296317 | 8.36 |
| San Francisco | 865933 | 2.19 |
| San Joaquin | 771406 | 1.96 |
| San Luis Obispo | 282771 | 0.72 |
| San Mateo | 762488 | 1.93 |
| Santa Barbara | 447651 | 1.14 |
| Santa Clara | 1932022 | 4.90 |
| Santa Cruz | 272138 | 0.69 |
| Shasta | 181935 | 0.46 |
| Sierra | 3079 | 0.01 |
| Siskiyou | 44151 | 0.11 |
| Solano | 451432 | 1.14 |
| Sonoma | 492498 | 1.25 |
| Stanislaus | 550842 | 1.40 |
| Sutter | 99080 | 0.25 |
| Tehama | 65345 | 0.17 |
| Trinity | 15818 | 0.04 |
| Tulare | 470999 | 1.19 |
| Tuolumne | 55243 | 0.14 |
| Ventura | 845255 | 2.14 |
| Yolo | 216703 | 0.55 |
| Yuba | 80404 | 0.20 |