California Population By County in 2018
Updated on April 4, 2021.

According to the US Census Bureau population estimates, there were 39,461,588 people living in California in 2018. Los Angeles was the most populated county with 10,073,906 residents, followed by San Diego with 3,333,861 residents, and Orange with 3,175,973 residents. Alpine with a population of 1,089 was the least populated county in California in 2018.

Use the map below to interactively explore the population of each county in California in 2018. The data can also be explored further by sorting and filtering with the table below.

Hover/Click on the counties to see the values.
California Population By County in 2018
See also Population estimate for other years:
Table of California Population By County in 2018
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County Population % of State Population
Alameda 1,666,756 4.22%
Alpine 1,089 0.00%
Amador 39,405 0.10%
Butte 230,339 0.58%
Calaveras 45,698 0.12%
Colusa 21,418 0.05%
Contra Costa 1,150,519 2.92%
Del Norte 27,740 0.07%
El Dorado 190,746 0.48%
Fresno 991,950 2.51%
Glenn 27,967 0.07%
Humboldt 136,244 0.35%
Imperial 181,523 0.46%
Inyo 17,946 0.05%
Kern 893,758 2.27%
Kings 151,382 0.38%
Lake 64,317 0.16%
Lassen 30,618 0.08%
Los Angeles 10,073,906 25.53%
Madera 156,882 0.40%
Marin 259,662 0.66%
Mariposa 17,405 0.04%
Mendocino 87,401 0.22%
Merced 274,151 0.70%
Modoc 8,800 0.02%
Mono 14,403 0.04%
Monterey 433,950 1.10%
Napa 138,789 0.35%
Nevada 99,508 0.25%
Orange 3,175,973 8.05%
Placer 392,330 0.99%
Plumas 18,741 0.05%
Riverside 2,445,789 6.20%
Sacramento 1,538,746 3.90%
San Benito 61,467 0.16%
San Bernardino 2,166,753 5.49%
San Diego 3,333,861 8.45%
San Francisco 880,696 2.23%
San Joaquin 752,491 1.91%
San Luis Obispo 283,354 0.72%
San Mateo 768,681 1.95%
Santa Barbara 445,780 1.13%
Santa Clara 1,932,337 4.90%
Santa Cruz 273,841 0.69%
Shasta 179,709 0.46%
Sierra 2,997 0.01%
Siskiyou 43,550 0.11%
Solano 445,725 1.13%
Sonoma 498,643 1.26%
Stanislaus 548,126 1.39%
Sutter 96,348 0.24%
Tehama 64,018 0.16%
Trinity 12,567 0.03%
Tulare 464,589 1.18%
Tuolumne 54,387 0.14%
Ventura 848,142 2.15%
Yolo 220,118 0.56%
Yuba 77,557 0.20%