Idaho Counties Directory & Interactive Map
Complete official guide to all 44 counties in Idaho (ID). Explore 2024 US Census population estimates, county seats, FIPS codes, land areas, and interactive mapping tools powered by GeoMap Suite.
Idaho County Breakdown
Showing 6 of 6 documented counties and seats.
County Name | FIPS | County Seat | Population (Census) | Land Area | Quick Tool |
|---|---|---|---|---|---|
| Ada County | 16001 | Boise | 494,965 | 1,055 sq mi | Lookup |
| Canyon County | 16027 | Caldwell | 231,105 | 587 sq mi | Lookup |
| Kootenai County | 16055 | Coeur d’Alene | 171,362 | 1,245 sq mi | Lookup |
| Bonneville County | 16019 | Idaho Falls | 123,964 | 1,869 sq mi | Lookup |
| Twin Falls County | 16083 | Twin Falls | 90,218 | 1,925 sq mi | Lookup |
| Bannock County | 16005 | Pocatello | 87,018 | 1,113 sq mi | Lookup |
Geographic Structure of Idaho Counties
County Administration & Governance
In Idaho, county governments manage vital public infrastructure, tax assessments, law enforcement, judicial courts, election administration, and public records. The county seat (Boise and other municipal headquarters) houses the primary courthouse, commissioners, and sheriff’s department.
All Idaho counties carry a unique 5-digit Federal Information Processing Standard (FIPS) code, where the first two digits (16) designate the state and the remaining three digits identify each specific jurisdiction.
Geographic & Demographic Highlights
- Most Populous County:Ada County (494,965 residents)
- Largest by Land Area:Twin Falls County (1,925 sq mi)
- State Capital:Boise
- 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.