Gainesville is a census-designated place (CDP) in western Prince William County, Virginia, United States. The population was 11,481 in the 2010 census.
Gainesville was once a changing point for stagecoach horses on the Fauquier & Alexandria Turnpike. In earlier times, the village that became known as “Gainesville” actually had two other names, if only briefly. In colonial days, the region was known as the “Middle Grounds,” in reference to its location between Broad Run and Bull Run. In the early 1800s, Samuel Love of Buckland Hall started work on the Warrenton-Alexandria Turnpike. In the hamlet where the turnpike passed through the Middle Grounds, a new stable was erected for stagecoach drivers to switch horses. Other businesses followed, and the settlement became known as New Stable. In 1846, a post office by that name was opened there in Richard Graham’s hotel and store. Mr. Graham also operated a large stable that catered to the drovers and stage drivers and other less pretentious travelers.