CITY · WA

What county is Seattle, WA in?

Seattle, WA is mostly in King County. County FIPS code 53033, population 2,271,380 (2023 estimate).

County details

City: Seattle, Washington
Primary county: King County
FIPS code: 53033
County population: 2,271,380

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

Questions

What county is Seattle in?

Seattle, WA is mostly in King County.

What is the county seat of King 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.