California Population By County in 2018
Updated on January 27, 2024.
According to the US Census Bureau population estimates, there were 39,437,463 people living in California in 2018. Los Angeles County was the most populated county with 10,061,533 residents, followed by San Diego County with 3,332,483 residents, and Orange County with 3,175,579 residents. Alpine County with a population of 1,081 was the least populated county in California in 2018.
Use the map below to interactively explore the population for each county in California in 2018. The data can also be explored further by sorting and filtering with the table below.
You can see similar information for other states and by state for the United States.
Related Topics: California Census Vintage Data Topic List.
Data Source: US Census Bureau (Vintage).
See this for other years:
California Population By County in 2018
Table of California Population By County in 2018
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| County | Population | % of State Population |
|---|---|---|
| Alameda | 1,666,596 | 4.23% |
| Alpine | 1,081 | 0.00% |
| Amador | 39,349 | 0.10% |
| Butte | 230,330 | 0.58% |
| Calaveras | 45,747 | 0.12% |
| Colusa | 21,389 | 0.05% |
| Contra Costa | 1,150,840 | 2.92% |
| Del Norte | 27,793 | 0.07% |
| El Dorado | 190,925 | 0.48% |
| Fresno | 991,298 | 2.51% |
| Glenn | 27,899 | 0.07% |
| Humboldt | 136,502 | 0.35% |
| Imperial | 181,062 | 0.46% |
| Inyo | 17,894 | 0.05% |
| Kern | 893,618 | 2.27% |
| Kings | 151,221 | 0.38% |
| Lake | 64,394 | 0.16% |
| Lassen | 30,658 | 0.08% |
| Los Angeles | 10,061,533 | 25.51% |
| Madera | 156,373 | 0.40% |
| Marin | 260,091 | 0.66% |
| Mariposa | 17,361 | 0.04% |
| Mendocino | 87,549 | 0.22% |
| Merced | 273,733 | 0.69% |
| Modoc | 8,816 | 0.02% |
| Mono | 14,400 | 0.04% |
| Monterey | 433,359 | 1.10% |
| Napa | 138,620 | 0.35% |
| Nevada | 99,472 | 0.25% |
| Orange | 3,175,579 | 8.05% |
| Placer | 392,735 | 1.00% |
| Plumas | 18,830 | 0.05% |
| Riverside | 2,443,221 | 6.20% |
| Sacramento | 1,539,550 | 3.90% |
| San Benito | 61,415 | 0.16% |
| San Bernardino | 2,165,627 | 5.49% |
| San Diego | 3,332,483 | 8.45% |
| San Francisco | 879,676 | 2.23% |
| San Joaquin | 752,590 | 1.91% |
| San Luis Obispo | 283,250 | 0.72% |
| San Mateo | 768,410 | 1.95% |
| Santa Barbara | 445,137 | 1.13% |
| Santa Clara | 1,931,985 | 4.90% |
| Santa Cruz | 273,713 | 0.69% |
| Shasta | 179,666 | 0.46% |
| Sierra | 2,961 | 0.01% |
| Siskiyou | 43,624 | 0.11% |
| Solano | 445,931 | 1.13% |
| Sonoma | 497,221 | 1.26% |
| Stanislaus | 547,855 | 1.39% |
| Sutter | 96,348 | 0.24% |
| Tehama | 63,904 | 0.16% |
| Trinity | 12,598 | 0.03% |
| Tulare | 464,279 | 1.18% |
| Tuolumne | 54,250 | 0.14% |
| Ventura | 847,222 | 2.15% |
| Yolo | 220,082 | 0.56% |
| Yuba | 77,418 | 0.20% |