CITY · ID
What county is Boise, ID in?
Boise, ID is mostly in Ada County. County FIPS code 16001, population 524,673 (2023 estimate).
County details
- City
- Boise, Idaho
- Primary county
- Ada County
- FIPS code
- 16001
- County population
- 524,673
Some cities extend into more than one county. Boise is placed in the county that contains its center. For a specific address, use the address lookup.
Questions
What county is Boise in?
Boise, ID is mostly in Ada County.
What is the county seat of Ada 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.