Manassas, formerly Manassas Junction, is an independent city in the Commonwealth of Virginia, United States. The population was 42,772 at the 2020 Census. It is the county seat of Prince William County, although the two are separate jurisdictions. Manassas borders the independent city of Manassas Park. The Bureau of Economic Analysis includes both Manassas and Manassas Park with Prince William County for statistical purposes.