Hart Mountain is a fault-block mountain in southern Oregon, about 30 miles east of Lakeview, rising above the Warner Valley as a single mountain rather than a range. Its highest summits are Warner Peak at 8,024 feet and Hart Peak at 7,724 feet. The mountain was named for the heart-shaped cattle brand used by pioneer ranchers Henry C. Wilson and his son-in-law C. G. Alexander, whose ranch stood at its base. Its upper slopes lie within Hart Mountain National Antelope Refuge, known for pronghorn antelope and bighorn sheep, while the Warner Wetlands ACEC at its western base protects wetland habitat for waterfowl and other wildlife.