
Philadelphia County
- State:
- Pennsylvania
- County Seat:
- Philadelphia
Philadelphia County's estimated 2025 population is 1,517,954 with a growth rate of -1.06% in the past year according to the most recent United States census data. Philadelphia County is the 1st largest county in Pennsylvania. The 2010 population was 1,528,303 and has seen a growth of -0.68% since that time.