Frederick -- U.S. County in Virginia Population (2000): 59209 Housing Units (2000): 23319 Land area (2000): 414.626136 sq. miles (1073.876718 sq. km) Water area (2000): 0.995932 sq. miles (2.579453 sq. km) Total area (2000): 415.622068 sq. miles (1076.456171 sq. km) Located within: Virginia (VA), FIPS 51 Location: 39.192751 N, 78.244616 W Headwords: Frederick Frederick, VA Frederick County Frederick County, VA