Furnace Mountain is the tallest peak of Catoctin Mountain in Loudoun County, Virginia. It rises steeply from the southern banks of the Potomac River across from Point of Rocks, Maryland and continues southward for 1 mile (1.6 km), reaching an elevation of 891 feet (272 m) before falling to a gap between it and an unnamed peak of 800 feet (240 m). Its name arises from the iron furnaces located at its base, which operated from the 1790s to the 1870s.