California Population By County in 2021

Updated on August 1, 2024.

Based on the US Census Vintage data estimates, in 2021, the population of California was 39,145,060. Among all California counties, Los Angeles had the highest population (9,809,462), followed by San Diego (3,274,432), and Orange (3,160,611). Alpine was the least populated county (1,229).

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.

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California Population By County in 2021
California Population By County in 2021
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County Population % of State Population
Alameda 1644047 4.20
Alpine 1229 0.00
Amador 41228 0.11
Butte 206336 0.53
Calaveras 46249 0.12
Colusa 21919 0.06
Contra Costa 1163941 2.97
Del Norte 27584 0.07
El Dorado 193704 0.50
Fresno 1013103 2.59
Glenn 28718 0.07
Humboldt 134897 0.35
Imperial 179138 0.46
Inyo 18924 0.05
Kern 912709 2.33
Kings 152775 0.39
Lake 68645 0.18
Lassen 31885 0.08
Los Angeles 9809462 25.06
Madera 158966 0.41
Marin 259278 0.66
Mariposa 17127 0.04
Mendocino 91321 0.23
Merced 284610 0.73
Modoc 8641 0.02
Mono 13271 0.03
Monterey 437158 1.12
Napa 136265 0.35
Nevada 103517 0.26
Orange 3160611 8.07
Placer 413047 1.06
Plumas 19958 0.05
Riverside 2453399 6.27
Sacramento 1588810 4.06
San Benito 66709 0.17
San Bernardino 2193087 5.60
San Diego 3274432 8.37
San Francisco 811935 2.07
San Joaquin 788354 2.01
San Luis Obispo 279464 0.71
San Mateo 739149 1.89
Santa Barbara 437521 1.12
Santa Clara 1885173 4.82
Santa Cruz 260475 0.67
Shasta 182135 0.47
Sierra 3294 0.01
Siskiyou 44139 0.11
Solano 450653 1.15
Sonoma 484519 1.24
Stanislaus 552723 1.41
Sutter 99152 0.25
Tehama 65446 0.17
Trinity 16082 0.04
Tulare 477176 1.22
Tuolumne 55131 0.14
Ventura 839471 2.15
Yolo 213141 0.54
Yuba 83227 0.21