California 2015 Population By County
Updated on December 2, 2021.

According to the US Census Bureau population estimates, there were 38,904,296 people living in California in 2015. Los Angeles County was the most populated county with 10,077,263 residents, followed by San Diego County with 3,280,825 residents, and Orange County with 3,148,952 residents. Alpine County with a population of 1,080 was the least populated county in California in 2015.

Use the map below to interactively explore the population of each county in California in 2015. The data can also be explored further by sorting and filtering with the table below.

California 2015 Population By County
See also Population estimate for other years:
Table of California 2015 Population By County
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County Population % of State Population
Alameda 1,634,326 4.20
Alpine 1,080 0.00
Amador 37,039 0.10
Butte 224,643 0.58
Calaveras 44,972 0.12
Colusa 21,208 0.06
Contra Costa 1,124,148 2.89
Del Norte 27,198 0.07
El Dorado 184,627 0.48
Fresno 968,889 2.49
Glenn 27,723 0.07
Humboldt 135,177 0.35
Imperial 178,701 0.46
Inyo 18,097 0.05
Kern 876,548 2.25
Kings 149,960 0.39
Lake 64,266 0.17
Lassen 31,256 0.08
Los Angeles 10,077,263 25.90
Madera 153,448 0.39
Marin 260,974 0.67
Mariposa 17,653 0.05
Mendocino 87,131 0.22
Merced 266,133 0.68
Modoc 9,064 0.02
Mono 14,074 0.04
Monterey 430,178 1.11
Napa 140,766 0.36
Nevada 98,716 0.25
Orange 3,148,952 8.09
Placer 372,870 0.96
Plumas 18,435 0.05
Riverside 2,344,648 6.03
Sacramento 1,493,547 3.84
San Benito 58,276 0.15
San Bernardino 2,114,352 5.44
San Diego 3,280,825 8.43
San Francisco 863,237 2.22
San Joaquin 721,919 1.86
San Luis Obispo 280,138 0.72
San Mateo 765,479 1.97
Santa Barbara 442,051 1.14
Santa Clara 1,915,736 4.92
Santa Cruz 273,495 0.70
Shasta 178,386 0.46
Sierra 2,990 0.01
Siskiyou 43,275 0.11
Solano 433,378 1.11
Sonoma 500,598 1.29
Stanislaus 532,954 1.37
Sutter 95,224 0.25
Tehama 63,150 0.16
Trinity 13,094 0.03
Tulare 456,794 1.17
Tuolumne 53,599 0.14
Ventura 845,599 2.17
Yolo 211,998 0.55
Yuba 74,039 0.19