Frederick County is located in the Commonwealth of Virginia. As of the 2020 census, the population was 91,419. Its county seat is Winchester. The county was formed in 1743 by the splitting of Orange County. It is Virginia's northernmost county.

Population: 95,051 (2022)
Area: 416 mi²
Cities: Stephens City, Middletown, Gore, Shawnee Land, Brucetown
Congressional district: 6th
Founded: 1743
Named for: Frederick, Prince of Wales
Seat: Winchester