West Mifflin, Pennsylvania

West Mifflin, Pennsylvania
Location in Allegheny County and the U.S. state of Pennsylvania.
Coordinates: 40°22′5″N 79°53′51″W / 40.36806°N 79.89750°W / 40.36806; -79.89750
Country United States
State Pennsylvania
CountyAllegheny
Incorporated1788 (Mifflin Township)
 Dec. 11, 1942 (Borough)
Government
  MayorChris Kelly
  CouncilJohn Inglis
Karen Santoro
Michael Moses
Robert Kostelnik
Joyce Kushner
Steve Marone
Scott Stephenson
  Borough ManagerBrian Kamauf
Area
  Total
14.50 sq mi (37.56 km2)
  Land14.21 sq mi (36.79 km2)
  Water0.29 sq mi (0.76 km2)  1.8%
Population
 (2020)
  Total
19,589
  Estimate 
(2019)
19,699
  Density1,386.67/sq mi (535.38/km2)
Time zoneUTC-5 (EST)
  Summer (DST)UTC-4 (EDT)
ZIP code
15122
Area code878
FIPS code42-83512
Websitewestmifflinborough.com

West Mifflin is a borough in Allegheny County, Pennsylvania, United States, located southeast of downtown Pittsburgh. The population was 19,589 at the 2020 census. It is named after Thomas Mifflin, 1st Governor of Pennsylvania, signer of the United States Constitution, and 1st Quartermaster General of the United States Army.

Although the borough is heavily residential, it is home to one of America's oldest traditional amusement parks, Kennywood Park. Other employers include advanced naval nuclear propulsion technology research and development facility, Bettis Atomic Power Laboratory; monorail manufacturer Bombardier; US Steel's Mon Valley Works–Irvin Plant; Community College of Allegheny County's South Campus; and the Allegheny County Airport.