California Counties, Demographics & Geography
Complete official guide to all 58 counties in California (CA). Explore 2024 US Census population estimates, county seats, FIPS codes, land areas, and interactive mapping tools powered by GeoMap Suite.
California County Breakdown
Showing 14 of 14 documented counties and seats.
County Name | FIPS | County Seat | Population (Census) | Land Area | Quick Tool |
|---|---|---|---|---|---|
| Los Angeles County | 06037 | Los Angeles | 9,721,138 | 4,058 sq mi | Lookup |
| San Diego County | 06073 | San Diego | 3,276,208 | 4,207 sq mi | Lookup |
| Orange County | 06059 | Santa Ana | 3,151,184 | 791 sq mi | Lookup |
| Riverside County | 06065 | Riverside | 2,458,395 | 7,206 sq mi | Lookup |
| San Bernardino County | 06071 | San Bernardino | 2,181,654 | 20,057 sq mi | Lookup |
| Santa Clara County | 06085 | San Jose | 1,877,592 | 1,290 sq mi | Lookup |
| Alameda County | 06001 | Oakland | 1,628,997 | 739 sq mi | Lookup |
| Sacramento County | 06067 | Sacramento | 1,585,055 | 965 sq mi | Lookup |
| Contra Costa County | 06013 | Martinez | 1,155,677 | 716 sq mi | Lookup |
| Fresno County | 06019 | Fresno | 1,015,190 | 5,958 sq mi | Lookup |
| Kern County | 06029 | Bakersfield | 909,235 | 8,132 sq mi | Lookup |
| Ventura County | 06111 | Ventura | 832,605 | 1,843 sq mi | Lookup |
| San Francisco County | 06075 | San Francisco | 808,437 | 47 sq mi | Lookup |
| San Joaquin County | 06077 | Stockton | 779,233 | 1,391 sq mi | Lookup |
Geographic Structure of California Counties
County Administration & Governance
In California, county governments manage vital public infrastructure, tax assessments, law enforcement, judicial courts, election administration, and public records. The county seat (Los Angeles and other municipal headquarters) houses the primary courthouse, commissioners, and sheriff’s department.
All California counties carry a unique 5-digit Federal Information Processing Standard (FIPS) code, where the first two digits (06) designate the state and the remaining three digits identify each specific jurisdiction.
Geographic & Demographic Highlights
- Most Populous County:Los Angeles County (9,721,138 residents)
- Largest by Land Area:San Bernardino County (20,057 sq mi)
- State Capital:Sacramento
- Census Bureau Region:West United States
Demographic calculations derive from the United States Census Bureau 2024 Population Estimates Program (PEP) and TIGER/Line geographic boundary files.