Oak Hill is a suburban unincorporated community located in Fairfax County, Virginia, United States. Oak Hill is located in Fairfax County, just east of Washington Dulles International Airport and south of the Dulles Toll and Access Roads. The town of Herndon lies immediately to the north, while the unincorporated community of Chantilly is adjacent to Oak H…Oak Hill is a suburban unincorporated community located in Fairfax County, Virginia, United States. Oak Hill is located in Fairfax County, just east of Washington Dulles International Airport and south of the Dulles Toll and Access Roads. The town of Herndon lies immediately to the north, while the unincorporated community of Chantilly is adjacent to Oak Hill in the south. Franklin Farm, Floris and McNair are census-designated places located within the larger Oak Hill community.