Prince William County built its third county courthouse on this site in 1762. This courthouse served as the county seat until 1822 when a new courthouse was built at Brentsville.
The Dumfries courthouse was where the Prince William Resolves were drafted in 1774. These resolutions supported the colonists in Boston and their protest against the importation of British goods due to increased taxes and the closure of Boston harbor.
The courthouse is also where William Grayson organized the first company of volunteers from Prince William County to fight in the Revolution. Hessian officers were kept prisoner in town and a large smallpox vaccination camp for the Continental Army was located nearby.
The historical marker can be found at the following GPS coordinates: 38° 34.058′ N, 77° 19.72′ W