Mercer County, Pennsylvania

Mercer County
Mercer County Courthouse (1909)
Location within the U.S. state of Pennsylvania
Pennsylvania's location within the U.S.
Coordinates: 41°19′N 80°15′W / 41.31°N 80.25°W / 41.31; -80.25
Country United States
State Pennsylvania
FoundedNovember 7, 1803
Named afterHugh Mercer
SeatMercer
Largest cityHermitage
Area
  Total
683 sq mi (1,770 km2)
  Land673 sq mi (1,740 km2)
  Water10 sq mi (30 km2)  1.5%
Population
 (2020)
  Total
110,652
  Estimate 
(2024)
108,140
  Density160.7/sq mi (62.0/km2)
Time zoneUTC−5 (Eastern)
  Summer (DST)UTC−4 (EDT)
Congressional district16th
Websitewww.mercercountypa.gov

Mercer County is a county in the Commonwealth of Pennsylvania. As of the 2020 census, the population was 110,652. Its county seat is Mercer, and its largest city is Hermitage. The county is part of the Northwest Pennsylvania region of the state.

Mercer County compromises the Hermitage, PA Micropolitan Statistical Area, which is included in the Greater Pittsburgh area.