Monongalia County, West Virginia

Monongalia County
Location within the U.S. state of West Virginia
West Virginia's location within the U.S.
Coordinates: 39°38′N 80°03′W / 39.63°N 80.05°W / 39.63; -80.05
Country United States
State West Virginia
FoundedOctober 9, 1776
Named afterLatin name for the Monongahela River
SeatMorgantown
Largest cityMorgantown
Area
  Total
366 sq mi (950 km2)
  Land360 sq mi (900 km2)
  Water5.8 sq mi (15 km2)  1.6%
Population
 (2020)
  Total
105,822
  Estimate 
(2021)
106,387
  Density296/sq mi (114/km2)
Time zoneUTC−5 (Eastern)
  Summer (DST)UTC−4 (EDT)
Congressional district2nd
Websitewww.co.monongalia.wv.us

Monongalia County, known locally as Mon County, is a county located in the U.S. state of West Virginia. As of the 2020 census, the population was 105,822, making it West Virginia's third-most populous county. Its county seat is Morgantown. The county was founded in 1776. Monongalia County is included in the Morgantown, WV Metropolitan Statistical Area, and is the largest county in North-Central West Virginia. It is part of the Pittsburgh media market.