Prince William County lies beside the Potomac River in the U.S. state of Virginia. At the 2020 census, the population was 482,204, making it Virginia's second most populous county. The county seat is the independent city of Manassas.

Cities: Woodbridge, Gainesville, Haymarket, Dumfries, Bristow
Meals tax: 4% pwcva.gov
Area code: 703/571
County seat: Manassas
Founded: 1731
Largest community: Dale City
Named for: Prince William, Duke of Cumberland