Catoctin Mountain traverses Frederick County, Maryland, and extends into northern Loudoun County, Virginia. It rises to its greatest elevation of above sea level just southwest of Cunningham Falls State Park and is transected by gaps at Braddock Heights (Fairview Pass), Point of Rocks on the Potomac River and Clarke's Gap west of Leesburg, as well as several other unnamed passes in Maryland and Virginia. The mountain is much lower in elevation in Virginia, reaching its highest peak just south of the Potomac at Furnace Mountain (891 feet/271 m) and with only one peak above south of Leesburg.