Lone Mountain () is in the Madison Range in the U.S. state of Montana. The summit is located in Lee Metcalf Wilderness within Gallatin and Beaverhead-Deerlodge National Forests. Lone Mountain is north of Koch Peak.
The mountain's rock is igneous in nature, but its magma did not reach the surface, so it is considered the laccolith rather than a true volcano.
The east, north, and southern slopes of Lone Peak are occupied by Big Sky Resort.