
Idaho County
- State:
- Idaho
- County Seat:
- Grangeville
Idaho County's estimated 2025 population is 18,396 with a growth rate of 1.39% in the past year according to the most recent United States census data. Idaho County is the 20th largest county in Idaho. The 2010 population was 16,311 and has seen a growth of 12.78% since that time.