California counties by area
Official, comparable measurements for 58 counties and county equivalents.
- 46.7–793.2 mi²
- 821.7–1,388.7 mi²
- 1,391–2,136.7 mi²
- 2,220.9–3,948.2 mi²
- 4,060.3–20,068.4 mi²
- 1.4–21 per mi²
- 22–79 per mi²
- 86–153 per mi²
- 162–554 per mi²
- 582–17,695 per mi²
Understanding California’s county areas
The land-area range runs from San Francisco County at 46.7 mi² to San Bernardino County at 20,068.4 mi². The largest has 429.9 times the land area of the smallest and accounts for 12.9% of the combined county land in California. Compare with every state’s largest county.
The median county-equivalent land area is 1,535.7 mi², above the national median of 604.5 mi². The median describes the middle of the county size distribution; it does not describe how people or development are distributed. A state with a few very large counties can have a much smaller median than its largest entry suggests.
Where water changes the picture
Santa Barbara County has the most assigned water area, at 1,053.8 mi². San Francisco County has the highest water share, with water making up 79.9% of its total area. Water area and water percentage answer different questions: the first measures an amount, while the second measures the mix of land and water.
Across all 58 entries, water accounts for 4.8% of the combined total area. This is calculated from the summed land and water measurements, rather than averaging county percentages, which would give each small and large county equal weight.
Where people live
An estimated 39,355,309 people lived in California on July 1, 2025 (−0.5% since 2020), or 11.4% of the national total in this dataset. Los Angeles County is the most populous county equivalent, with 9,694,934 residents — 24.6% of the state. The largest by land, San Bernardino County, has 2,224,091.
Across the state there are 253 people per square mile of land. County densities range from 17,695 in San Francisco County to 1.4 in Alpine County; the median county equivalent has 112. Switch the map above to density to see where the state’s population concentrates.
Compare the largest and smallest county equivalents in California to see land, water, and total area on the same scale.
These calculations use the 2026 Census county records listed below. County-equivalent boundaries vary between states; area alone does not measure population, density, or usable land. See coverage and calculation rules.
Complete area table
Sorted from largest to smallest land area.
| # | County / equivalent | Land | Water | Water share | Population | Per mi² |
|---|---|---|---|---|---|---|
| 1 | San Bernardino CountyGEOID 06071 | 20,068.4 mi² | 37.2 mi² | 0.2% | 2,224,091 | 111 |
| 2 | Inyo CountyGEOID 06027 | 10,197.3 mi² | 29.8 mi² | 0.3% | 18,158 | 1.8 |
| 3 | Kern CountyGEOID 06029 | 8,134.7 mi² | 30.2 mi² | 0.4% | 927,068 | 114 |
| 4 | Riverside CountyGEOID 06065 | 7,209 mi² | 93.6 mi² | 1.3% | 2,544,916 | 353 |
| 5 | Siskiyou CountyGEOID 06093 | 6,278.8 mi² | 69.2 mi² | 1.1% | 42,013 | 6.7 |
| 6 | Fresno CountyGEOID 06019 | 5,958.6 mi² | 52.8 mi² | 0.9% | 1,035,456 | 174 |
| 7 | Tulare CountyGEOID 06107 | 4,823.9 mi² | 14.4 mi² | 0.3% | 485,146 | 101 |
| 8 | Lassen CountyGEOID 06035 | 4,541.4 mi² | 178.7 mi² | 3.8% | 28,117 | 6.2 |
| 9 | San Diego CountyGEOID 06073 | 4,210.9 mi² | 315 mi² | 7% | 3,282,248 | 779 |
| 10 | Imperial CountyGEOID 06025 | 4,175.5 mi² | 305.1 mi² | 6.8% | 181,411 | 43 |
| 11 | Los Angeles CountyGEOID 06037 | 4,060.3 mi² | 689.1 mi² | 14.5% | 9,694,934 | 2,388 |
| 12 | Modoc CountyGEOID 06049 | 3,948.2 mi² | 255 mi² | 6.1% | 8,426 | 2.1 |
| 13 | Shasta CountyGEOID 06089 | 3,775.6 mi² | 71.8 mi² | 1.9% | 181,648 | 48 |
| 14 | Humboldt CountyGEOID 06023 | 3,568 mi² | 484.2 mi² | 11.9% | 131,647 | 37 |
| 15 | Mendocino CountyGEOID 06045 | 3,506.8 mi² | 371.3 mi² | 9.6% | 88,122 | 25 |
| 16 | San Luis Obispo CountyGEOID 06079 | 3,300.8 mi² | 314.9 mi² | 8.7% | 282,367 | 86 |
| 17 | Monterey CountyGEOID 06053 | 3,281.7 mi² | 489.5 mi² | 13% | 433,729 | 132 |
| 18 | Trinity CountyGEOID 06105 | 3,179.3 mi² | 28.3 mi² | 0.9% | 15,720 | 4.9 |
| 19 | Mono CountyGEOID 06051 | 3,048.9 mi² | 82.9 mi² | 2.6% | 12,505 | 4.1 |
| 20 | Tehama CountyGEOID 06103 | 2,949.1 mi² | 13 mi² | 0.4% | 64,665 | 22 |
| 21 | Santa Barbara CountyGEOID 06083 | 2,733.9 mi² | 1,053.8 mi² | 27.8% | 442,065 | 162 |
| 22 | Plumas CountyGEOID 06063 | 2,553.1 mi² | 60.4 mi² | 2.3% | 18,583 | 7.3 |
| 23 | Tuolumne CountyGEOID 06109 | 2,220.9 mi² | 53.5 mi² | 2.4% | 53,160 | 24 |
| 24 | Madera CountyGEOID 06039 | 2,136.7 mi² | 16.3 mi² | 0.8% | 167,927 | 79 |
| 25 | Merced CountyGEOID 06047 | 1,938 mi² | 40.6 mi² | 2.1% | 297,260 | 153 |
| 26 | Ventura CountyGEOID 06111 | 1,840.8 mi² | 365.8 mi² | 16.6% | 830,851 | 451 |
| 27 | El Dorado CountyGEOID 06017 | 1,707.8 mi² | 78.5 mi² | 4.4% | 192,323 | 113 |
| 28 | Butte CountyGEOID 06007 | 1,636.5 mi² | 40.6 mi² | 2.4% | 209,211 | 128 |
| 29 | Sonoma CountyGEOID 06097 | 1,575.3 mi² | 192 mi² | 10.9% | 486,444 | 309 |
| 30 | Stanislaus CountyGEOID 06099 | 1,496.2 mi² | 17.9 mi² | 1.2% | 557,719 | 373 |
| 31 | Mariposa CountyGEOID 06043 | 1,448.8 mi² | 14 mi² | 1% | 16,918 | 12 |
| 32 | Placer CountyGEOID 06061 | 1,407.4 mi² | 94.8 mi² | 6.3% | 442,081 | 314 |
| 33 | San Joaquin CountyGEOID 06077 | 1,392.3 mi² | 34.3 mi² | 2.4% | 823,815 | 592 |
| 34 | Kings CountyGEOID 06031 | 1,391 mi² | 1.2 mi² | 0.1% | 154,327 | 111 |
| 35 | San Benito CountyGEOID 06069 | 1,388.7 mi² | 1.8 mi² | 0.1% | 70,082 | 50 |
| 36 | Glenn CountyGEOID 06021 | 1,313.9 mi² | 13 mi² | 1% | 28,141 | 21 |
| 37 | Santa Clara CountyGEOID 06085 | 1,291.1 mi² | 13 mi² | 1% | 1,914,391 | 1,483 |
| 38 | Lake CountyGEOID 06033 | 1,255.1 mi² | 73 mi² | 5.5% | 67,772 | 54 |
| 39 | Colusa CountyGEOID 06011 | 1,150.6 mi² | 5.7 mi² | 0.5% | 21,836 | 19 |
| 40 | Calaveras CountyGEOID 06009 | 1,020 mi² | 16.9 mi² | 1.6% | 46,605 | 46 |
| 41 | Yolo CountyGEOID 06113 | 1,013 mi² | 8.8 mi² | 0.9% | 224,410 | 222 |
| 42 | Del Norte CountyGEOID 06015 | 1,006.2 mi² | 223.5 mi² | 18.2% | 26,410 | 26 |
| 43 | Sacramento CountyGEOID 06067 | 965.4 mi² | 29 mi² | 2.9% | 1,618,460 | 1,677 |
| 44 | Nevada CountyGEOID 06057 | 957.8 mi² | 16 mi² | 1.6% | 101,911 | 106 |
| 45 | Sierra CountyGEOID 06091 | 953.2 mi² | 9 mi² | 0.9% | 3,098 | 3.3 |
| 46 | Solano CountyGEOID 06095 | 821.7 mi² | 84.4 mi² | 9.3% | 455,376 | 554 |
| 47 | Orange CountyGEOID 06059 | 793.2 mi² | 156.5 mi² | 16.5% | 3,149,507 | 3,970 |
| 48 | Napa CountyGEOID 06055 | 752 mi² | 40.3 mi² | 5.1% | 132,949 | 177 |
| 49 | Alpine CountyGEOID 06003 | 738.3 mi² | 4.8 mi² | 0.7% | 1,043 | 1.4 |
| 50 | Alameda CountyGEOID 06001 | 737.5 mi² | 83.7 mi² | 10.2% | 1,636,630 | 2,219 |
| 51 | Contra Costa CountyGEOID 06013 | 716.9 mi² | 87 mi² | 10.8% | 1,170,070 | 1,632 |
| 52 | Yuba CountyGEOID 06115 | 632 mi² | 12 mi² | 1.9% | 88,691 | 140 |
| 53 | Sutter CountyGEOID 06101 | 602.7 mi² | 5.7 mi² | 0.9% | 98,787 | 164 |
| 54 | Amador CountyGEOID 06005 | 594.6 mi² | 11.4 mi² | 1.9% | 41,876 | 70 |
| 55 | Marin CountyGEOID 06041 | 520.1 mi² | 308 mi² | 37.2% | 253,694 | 488 |
| 56 | San Mateo CountyGEOID 06081 | 448.6 mi² | 292.4 mi² | 39.5% | 743,568 | 1,658 |
| 57 | Santa Cruz CountyGEOID 06087 | 445.1 mi² | 162.1 mi² | 26.7% | 258,852 | 582 |
| 58 | San Francisco CountyGEOID 06075 | 46.7 mi² | 185.2 mi² | 79.9% | 826,079 | 17,695 |