CITY · CA

What county is San Diego, CA in?

San Diego, CA is mostly in San Diego County. County FIPS code 06073, population 3,269,973 (2023 estimate).

County details

City: San Diego, California
Primary county: San Diego County
FIPS code: 06073
County population: 3,269,973

Some cities extend into more than one county. San Diego is placed in the county that contains its center. For a specific address, use the address lookup.

Questions

What county is San Diego in?

San Diego, CA is mostly in San Diego County.

What is the county seat of San Diego County?

County seats are not part of the data on this site. Check the county’s official website.

Can a city be in two counties?

Yes. Large cities such as Houston and Atlanta cross county lines. The address lookup shows the exact county for any street address.

Sources: U.S. Census Bureau geographic reference files; FCC Area API; Census Bureau Population Estimates, Vintage 2023. Last reviewed 2026-10-27.