Fairfax -- U.S. County in Virginia Population (2000): 969749 Housing Units (2000): 359411 Land area (2000): 395.044718 sq. miles (1023.161078 sq. km) Water area (2000): 11.566728 sq. miles (29.957688 sq. km) Total area (2000): 406.611446 sq. miles (1053.118766 sq. km) Located within: Virginia (VA), FIPS 51 Location: 38.840845 N, 77.249565 W Headwords: Fairfax Fairfax, VA Fairfax County Fairfax County, VA