Montgomery County, Pennsylvania

Montgomery County, Pennsylvania
Montgomery County Courthouse in Norristown, May 2007
Nickname: 
Montco
Location within the U.S. state of Pennsylvania
Coordinates: 40°13′N 75°22′W / 40.21°N 75.37°W / 40.21; -75.37
Country United States
State Pennsylvania
FoundedSeptember 10, 1784
Named afterRichard Montgomery or Montgomeryshire
SeatNorristown
Largest municipalityLower Merion Township
Government
 • County CommissionersNeil K. Makhija, Chair
Jamila H. Winder, Vice Chair
Thomas DiBello, Commissioner
Area
 • Total
487 sq mi (1,260 km2)
 • Land483 sq mi (1,250 km2)
 • Water4.2 sq mi (11 km2)  0.9%
Population
 (2020)
 • Total
856,553
 • Estimate 
(2024)
868,742
 • Density1,773/sq mi (685/km2)
Time zoneUTC−5 (Eastern)
 • Summer (DST)UTC−4 (EDT)
Congressional districts1st, 4th, 5th
Websitemontgomerycountypa.gov

Montgomery County, colloquially referred to as Montco, is in the Commonwealth of Pennsylvania. As of the 2020 census, the population of the county was 856,553, making it the third-most populous county in Pennsylvania after Philadelphia and Allegheny counties and the most populous county in Pennsylvania without a major city.

The county seat and largest city is Norristown. The county is part of the PhiladelphiaCamdenWilmington PA-NJDEMD metropolitan statistical area, known as the Delaware Valley, and marks the Delaware Valley's northern border with the Lehigh Valley region of eastern Pennsylvania.

The county borders Philadelphia, the nation's sixth-largest city, to its southeast, Bucks County to its east, Berks and Lehigh counties to its north, Delaware County to its south, and Chester County to its southwest.

The county was created on September 10, 1784, out of land originally part of Philadelphia County. The first courthouse was housed in Barley Sheaf Inn. The county is named after Richard Montgomery, an American Revolutionary War general killed on December 31, 1775 while attempting to capture Quebec City.