Dumfries, officially the Town of Dumfries, is a town in Prince William County, Virginia. The population was 4,961 at the 2010 United States Census.

Prince William Forest Park is a national park in the U.S. state of Virginia within Prince William County, located adjacent to the Marine Corps Base Quantico near the town of Dumfries. Established as Chopawamsic Recreational Demonstration Area in 1936, the park is the largest protected natural area in the Washington, D.C. metropolitan region at over 13,000 acres (5,300 ha).