Larch Mountain is a 2,664-foot summit in the Black Hills of Thurston County, Washington, and one of the range’s two highest peaks with Capitol Peak. It rises above nearby Rock Candy Mountain, which reaches 2,356 feet, and is the most prominent peak in Thurston County. Its importance is chiefly geographic, as a major high point in the Black Hills and part of the upland landscape that helps define this part of western Washington.