Gainesville is a census-designated place (CDP) in western Prince William County, Virginia, United States.

In the hamlet where the turnpike passed through the Middle Grounds, a new stable was erected for stagecoach drivers to switch horses.

The person responsible for bringing the railroad through the village was Thomas Brawner Gaines (1814-1856), who had begun buying up property in the area as early as 1835, and later became a major landowner.

[4] In 1850, Thomas Brawner Gaines (1814-1856) sold to the Manassas Gap Railroad a right-of-way through his land along the Warrenton Turnpike (US Route 29).

After the railroad was completed to Strasburg, Virginia in 1854, Gaines conveyed additional land for a train depot with the condition that the rail stop take his name.

Into the early 1940s the Southern Railway operated passenger service from Harrisonburg and Strasburg Junction through Gainesville, to Manassas and Washington's Union Station.

In 2006, the VDOT began working on the Gainesville Interchange improvement project, with construction officially starting in July 2011, in order to ease the traffic in the rapidly growing Gainesville-Haymarket area.

Major commercial and residential development has taken place since 2000, resulting in Gainesville having six large shopping centers.

Gainesville railway station extension for the VRE was scheduled to open in 2022, connecting the region via commuter rail to Fairfax County, Manassas, and Washington, D.C.

However, the project was voted down by the VRE Operations Board in favor of expanding services to the existing station in Broad Run.