This is a large Reservoir. At 2,100-acres, Occoquan forms the boundary between Fairfax and Prince William counties. It has three equipped marinas, which are rental facilities for watercrafts. You may also purchase food and fishing bait and tackle. Occoquan Reservoir serves the residents of Fairfax County and the City of Alexandria with their water needs. This is the ramp at the southern part of the lake.