California Population By County in 2021
Updated on June 16, 2025.
Based on the US Census Vintage data estimates, in 2021, the population of California was 39,142,565. Among all California counties, Los Angeles had the highest population (9,809,239), followed by San Diego (3,274,244), and Orange (3,159,351). Alpine was the least populated county (1,203).
Hover over or click on the counties in the map below to see the populations. The data can also be found in a table below. You can use the table to sort, filter, and explore the data further.
You can see similar information for other states and by state for the United States.
Related Topics: California Census Vintage Data Topic List.
Data Source: US Census Bureau (Vintage).
See this for other years:
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 | 1643856 | 4.20 |
| Alpine | 1203 | 0.00 |
| Amador | 41245 | 0.11 |
| Butte | 206351 | 0.53 |
| Calaveras | 46262 | 0.12 |
| Colusa | 21931 | 0.06 |
| Contra Costa | 1163813 | 2.97 |
| Del Norte | 27581 | 0.07 |
| El Dorado | 193724 | 0.50 |
| Fresno | 1012879 | 2.59 |
| Glenn | 28714 | 0.07 |
| Humboldt | 134978 | 0.35 |
| Imperial | 179206 | 0.46 |
| Inyo | 18920 | 0.05 |
| Kern | 912782 | 2.33 |
| Kings | 152724 | 0.39 |
| Lake | 68623 | 0.18 |
| Lassen | 31884 | 0.08 |
| Los Angeles | 9809239 | 25.06 |
| Madera | 159019 | 0.41 |
| Marin | 259254 | 0.66 |
| Mariposa | 17136 | 0.04 |
| Mendocino | 91303 | 0.23 |
| Merced | 284834 | 0.73 |
| Modoc | 8640 | 0.02 |
| Mono | 13263 | 0.03 |
| Monterey | 439245 | 1.12 |
| Napa | 136219 | 0.35 |
| Nevada | 103499 | 0.26 |
| Orange | 3159351 | 8.07 |
| Placer | 412968 | 1.06 |
| Plumas | 19965 | 0.05 |
| Riverside | 2455225 | 6.27 |
| Sacramento | 1588824 | 4.06 |
| San Benito | 66703 | 0.17 |
| San Bernardino | 2190877 | 5.60 |
| San Diego | 3274244 | 8.37 |
| San Francisco | 815498 | 2.08 |
| San Joaquin | 788096 | 2.01 |
| San Luis Obispo | 279468 | 0.71 |
| San Mateo | 739330 | 1.89 |
| Santa Barbara | 437117 | 1.12 |
| Santa Clara | 1878320 | 4.80 |
| Santa Cruz | 260904 | 0.67 |
| Shasta | 182243 | 0.47 |
| Sierra | 3298 | 0.01 |
| Siskiyou | 44144 | 0.11 |
| Solano | 450819 | 1.15 |
| Sonoma | 484561 | 1.24 |
| Stanislaus | 552939 | 1.41 |
| Sutter | 99121 | 0.25 |
| Tehama | 65467 | 0.17 |
| Trinity | 16102 | 0.04 |
| Tulare | 476939 | 1.22 |
| Tuolumne | 55126 | 0.14 |
| Ventura | 840009 | 2.15 |
| Yolo | 213545 | 0.55 |
| Yuba | 83035 | 0.21 |