|
Allegheny County Pennsylvania ☎ +1 412-350-4636 Last Updated: 06/27/2025 |
| Allegheny County is a county in Pennsylvania. As of the 2020 census, the population was 1,250,578, making it the state's second-most populous county, after Philadelphia County. Its county seat and most populous city is Pittsburgh, Pennsylvania's second most populous city. Allegheny County is home to world-renowned educational, cultural, research & health-care institutions. | |