California Population By County in 2020

Updated on June 16, 2025.

Based on the US Census Vintage data estimates, in 2020, the population of California was 39,521,958. Among all California counties, Los Angeles had the highest population (9,996,634), followed by San Diego (3,301,182), and Orange (3,186,261). Alpine was the least populated county (1,179).

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 2020
California Population By County in 2020
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County Population % of State Population
Alameda 1680614 4.25
Alpine 1179 0.00
Amador 40584 0.10
Butte 210222 0.53
Calaveras 45350 0.12
Colusa 21868 0.06
Contra Costa 1166165 2.95
Del Norte 27616 0.07
El Dorado 191250 0.48
Fresno 1009613 2.56
Glenn 28889 0.07
Humboldt 136324 0.35
Imperial 179730 0.46
Inyo 18999 0.05
Kern 906124 2.29
Kings 152797 0.39
Lake 68200 0.17
Lassen 32319 0.08
Los Angeles 9996634 25.29
Madera 156434 0.40
Marin 261341 0.66
Mariposa 17133 0.04
Mendocino 91362 0.23
Merced 282963 0.72
Modoc 8677 0.02
Mono 13225 0.03
Monterey 440506 1.12
Napa 137465 0.35
Nevada 102267 0.26
Orange 3186261 8.06
Placer 405951 1.03
Plumas 19761 0.05
Riverside 2424663 6.14
Sacramento 1586727 4.01
San Benito 64533 0.16
San Bernardino 2183526 5.53
San Diego 3301182 8.35
San Francisco 874826 2.21
San Joaquin 780676 1.98
San Luis Obispo 281924 0.71
San Mateo 762727 1.93
Santa Barbara 448083 1.13
Santa Clara 1924802 4.87
Santa Cruz 271768 0.69
Shasta 182190 0.46
Sierra 3229 0.01
Siskiyou 43999 0.11
Solano 452887 1.15
Sonoma 488501 1.24
Stanislaus 553710 1.40
Sutter 99479 0.25
Tehama 65690 0.17
Trinity 16095 0.04
Tulare 473944 1.20
Tuolumne 55397 0.14
Ventura 843808 2.13
Yolo 217768 0.55
Yuba 82001 0.21