Pennsylvania Counties by Population (2025)

There are 67 counties in Pennsylvania.

Philadelphia County is the largest county in the state, with a population of 1,584,483. The most recent census shows that its population has decreased by 0.01% since the previous census.

A number of other Pennsylvania counties also boast relatively large populations for their state, though not able to match the density of Philadelphia County:

• Allegheny County : 1,233,490
• Montgomery County : 886,707

Pennsylvania Counties with the Fewest Residents

The smallest county in Pennsylvania is Cameron County , with a population of just 4,314. This total represents a decrease of 0.0% since the last census count was performed.

Other small counties include:

• Sullivan County : 5,929
• Forest County : 6,716
• Fulton County : 14,394

Pennsylvania Counties with Rapid Growth

Pike County , with its current population of 63,256, has shown the largest population growth, with an increase of 0.1% since the last census.

Chester County has also had relatively high population growth of 0.06% with 566,180 residents.

On the other hand, Greene County has had the largest decrease in population, with its 33,427 current residents totalling 0.1% less than the previous census.