Lake Manassas is a 770-acre (310 ha) reservoir located in Prince William County, Virginia, to the southwest of Gainesville. It is owned and operated by the city of Manassas, Virginia, although it is located outside the city limits. The reservoir was created in the late 1960s to provide drinking water for area residents and became operational in 1970. Today it contributes to a regional water system which serves the cities of Manassas and Manassas Park, Virginia, and unincorporated areas of Prince William County. Several golf clubs have courses along the banks, including Stonewall Golf Club and Robert Trent Jones Golf Club.