California Population By County in 2015

Updated on January 29, 2024.

Based on the US Census Vintage data estimates, in 2015, the population of California was 38,904,296. Among all California counties, Los Angeles[object Promise] had the highest population (10,077,263), followed by San Diego[object Promise] (3,280,825), and Orange[object Promise] (3,148,952). Alpine[object Promise] was the least populated county (1,080).

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 2015
California Population By County in 2015
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County Population % of State Population
Alameda 1634326 4.20
Alpine 1080 0.00
Amador 37039 0.10
Butte 224643 0.58
Calaveras 44972 0.12
Colusa 21208 0.06
Contra Costa 1124148 2.89
Del Norte 27198 0.07
El Dorado 184627 0.48
Fresno 968889 2.49
Glenn 27723 0.07
Humboldt 135177 0.35
Imperial 178701 0.46
Inyo 18097 0.05
Kern 876548 2.25
Kings 149960 0.39
Lake 64266 0.17
Lassen 31256 0.08
Los Angeles 10077263 25.90
Madera 153448 0.39
Marin 260974 0.67
Mariposa 17653 0.05
Mendocino 87131 0.22
Merced 266133 0.68
Modoc 9064 0.02
Mono 14074 0.04
Monterey 430178 1.11
Napa 140766 0.36
Nevada 98716 0.25
Orange 3148952 8.09
Placer 372870 0.96
Plumas 18435 0.05
Riverside 2344648 6.03
Sacramento 1493547 3.84
San Benito 58276 0.15
San Bernardino 2114352 5.44
San Diego 3280825 8.43
San Francisco 863237 2.22
San Joaquin 721919 1.86
San Luis Obispo 280138 0.72
San Mateo 765479 1.97
Santa Barbara 442051 1.14
Santa Clara 1915736 4.92
Santa Cruz 273495 0.70
Shasta 178386 0.46
Sierra 2990 0.01
Siskiyou 43275 0.11
Solano 433378 1.11
Sonoma 500598 1.29
Stanislaus 532954 1.37
Sutter 95224 0.25
Tehama 63150 0.16
Trinity 13094 0.03
Tulare 456794 1.17
Tuolumne 53599 0.14
Ventura 845599 2.17
Yolo 211998 0.55
Yuba 74039 0.19