
Armstrong County
- State:
- Pennsylvania
- County Seat:
- Kittanning
Armstrong County's estimated 2025 population is 62,814 with a growth rate of -0.99% in the past year according to the most recent United States census data. Armstrong County is the 40th largest county in Pennsylvania. The 2010 population was 69,029 and has seen a growth of -9% since that time.