County facts · Land area · October 21, 2026
Largest Counties in California by Area and Population
The largest California counties by land area and by 2023 population, plus the smallest, county seats and a link to each official parcel map.
Looking for the largest counties in California? California has 58 counties covering about 155,858 square miles of land, based on the Census Bureau's 2020 Gazetteer. The largest by land area is San Bernardino County, at about 20,068 square miles, roughly 428 times the size of the smallest, San Francisco County (47 sq mi). Measured by people instead, the largest is Los Angeles County, with about 9,663,345 residents in the Census Bureau's July 1, 2023 estimate.
Each table below links the county's Platbookmapper page and its official parcel viewer, so you can go straight from the numbers to the property lines.
California counties at a glance
- Counties: 58
- Land area: about 155,858 sq mi, plus about 7,836 sq mi of water inside county lines
- Residents, 2023 estimates: about 38,965,193, or about 250 people per square mile of land
- Median county land area: about 1,536 sq mi
- With a verified public parcel viewer in our directory: 58 of 58
The 10 largest California counties by land area
| # | County | Seat | Land (sq mi) | 2023 pop. | People per sq mi | Parcel viewer |
|---|---|---|---|---|---|---|
| 1 | San Bernardino County | San Bernardino | 20,068 | 2,195,611 | 109 | county web map |
| 2 | Inyo County | Independence | 10,197 | 18,527 | 1.8 | ArcGIS Web AppBuilder |
| 3 | Kern County | Bakersfield | 8,135 | 913,820 | 112 | county web map |
| 4 | Riverside County | Riverside | 7,209 | 2,492,442 | 346 | county web map |
| 5 | Siskiyou County | Yreka | 6,279 | 42,905 | 6.8 | ArcGIS Experience Builder |
| 6 | Fresno County | Fresno | 5,958 | 1,017,162 | 171 | ArcGIS Web AppBuilder |
| 7 | Tulare County | Visalia | 4,824 | 479,468 | 99 | ArcGIS Web AppBuilder |
| 8 | Lassen County | Susanville | 4,541 | 28,861 | 6.4 | ArcGIS Experience Builder |
| 9 | San Diego County | San Diego | 4,210 | 3,269,973 | 777 | ArcGIS Map Viewer |
| 10 | Imperial County | El Centro | 4,176 | 179,057 | 43 | ArcGIS Web AppBuilder |
Together these 10 cover about 49% of California's land area and hold about 27% of its residents.
The 10 most populous California counties
| # | County | Seat | 2023 pop. | Land (sq mi) | Parcel viewer |
|---|---|---|---|---|---|
| 1 | Los Angeles County | Los Angeles | 9,663,345 | 4,059 | county web map |
| 2 | San Diego County | San Diego | 3,269,973 | 4,210 | ArcGIS Map Viewer |
| 3 | Orange County | Santa Ana | 3,135,755 | 793 | county web map |
| 4 | Riverside County | Riverside | 2,492,442 | 7,209 | county web map |
| 5 | San Bernardino County | San Bernardino | 2,195,611 | 20,068 | county web map |
| 6 | Santa Clara County | San Jose | 1,877,592 | 1,291 | county web map |
| 7 | Alameda County | Oakland | 1,622,188 | 737 | ArcGIS Web AppBuilder |
| 8 | Sacramento County | Sacramento | 1,584,288 | 965 | county web map |
| 9 | Contra Costa County | Martinez | 1,155,025 | 717 | county web map |
| 10 | Fresno County | Fresno | 1,017,162 | 5,958 | ArcGIS Web AppBuilder |
These 10 hold about 72% of California's residents in the 2023 estimates.
The 5 smallest California counties by land area
| County | Seat | Land (sq mi) | 2023 pop. | Parcel viewer |
|---|---|---|---|---|
| San Francisco County | San Francisco | 47 | 808,988 | county web map |
| Santa Cruz County | Santa Cruz | 445 | 261,547 | county web map |
| San Mateo County | Redwood City | 449 | 726,353 | county web map |
| Marin County | San Rafael | 520 | 254,407 | county web map |
| Amador County | Jackson | 595 | 41,811 | ArcGIS Experience Builder |
Most and least crowded
- Most people per square mile: San Francisco County, about 17,244 (then Orange County, 3,955, and Los Angeles County, 2,381)
- Fewest people per square mile: Alpine County, about 1.5 (then Inyo County, 1.8, and Modoc County, 2.2)
Counties with the most water
The Census Bureau reports water separately from land. It counts lakes, reservoirs, rivers and, for coastal and Great Lakes counties, the water inside the county boundary.
- Santa Barbara County: about 1,054 sq mi of water, 28% of its total area
- Los Angeles County: about 690 sq mi of water, 15% of its total area
- Monterey County: about 489 sq mi of water, 13% of its total area
Using these numbers in a land search
- Land area is not parcel count. A large rural county can hold fewer parcels than a small suburban one, so size alone says little about how busy its parcel map is.
- Search, don't scroll. In a big county, type an address, owner name or parcel number into the viewer's search box, where it has one, instead of panning across the map.
- Records follow the county line. Deeds, plats and tax bills are kept by the county where the parcel sits, so a tract that crosses a county line usually has a parcel number in each county.
- Rounded figures. Land and water areas are rounded to whole square miles. People per square mile is the 2023 estimate divided by land area.
Related guides
- California county GIS websites by viewer
- California plat maps
- California parcel map guide
- California landowner maps for hunting
- California–Nevada border counties
More: All California counties on Platbookmapper
Sources
- U.S. Census Bureau Gazetteer files, 2020 county land and water area.
- U.S. Census Bureau, Population Estimates Program, county totals, Vintage 2023 (July 1, 2023 estimates)
- Platbookmapper county GIS directory (live data file behind our county pages, pulled October 21, 2026) for each county's official parcel viewer.
- County seats: Wikidata (county seat property), cross-checked against Census place names.