California Population By County in 2021

Updated on January 29, 2024.

Based on the US Census Vintage data estimates, in 2021, the population of California was 39,142,991. Among all California counties, Los Angeles[object Promise] had the highest population (9,811,842), followed by San Diego[object Promise] (3,274,954), and Orange[object Promise] (3,161,005). Alpine[object Promise] was the least populated county (1,235).

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.

See this for other years:
California Population By County in 2021
California Population By County in 2021
Items per page:
0 of 0
County Population % of State Population
Alameda 1643837 4.20
Alpine 1235 0.00
Amador 41144 0.11
Butte 206190 0.53
Calaveras 46219 0.12
Colusa 21913 0.06
Contra Costa 1163298 2.97
Del Norte 27553 0.07
El Dorado 193590 0.50
Fresno 1012992 2.59
Glenn 28664 0.07
Humboldt 134836 0.34
Imperial 179215 0.46
Inyo 18927 0.05
Kern 912351 2.33
Kings 152679 0.39
Lake 68584 0.18
Lassen 31813 0.08
Los Angeles 9811842 25.07
Madera 158910 0.41
Marin 259162 0.66
Mariposa 17107 0.04
Mendocino 91003 0.23
Merced 284458 0.73
Modoc 8571 0.02
Mono 13261 0.03
Monterey 437249 1.12
Napa 136206 0.35
Nevada 103457 0.26
Orange 3161005 8.08
Placer 412789 1.06
Plumas 19940 0.05
Riverside 2453178 6.27
Sacramento 1588106 4.06
San Benito 66675 0.17
San Bernardino 2192882 5.60
San Diego 3274954 8.37
San Francisco 811253 2.07
San Joaquin 788140 2.01
San Luis Obispo 279298 0.71
San Mateo 739060 1.89
Santa Barbara 437434 1.12
Santa Clara 1886595 4.82
Santa Cruz 260495 0.67
Shasta 181981 0.47
Sierra 3295 0.01
Siskiyou 44026 0.11
Solano 450350 1.15
Sonoma 484315 1.24
Stanislaus 552851 1.41
Sutter 99038 0.25
Tehama 65380 0.17
Trinity 16061 0.04
Tulare 476946 1.22
Tuolumne 55065 0.14
Ventura 839358 2.14
Yolo 213039 0.54
Yuba 83216 0.21