Mount Massive is the second highest summit of the Rocky Mountains of North America and the U.S. state of Colorado. The prominent 14,428-foot (4,398 m) fourteener of the Sawatch Range is located in the Mount Massive Wilderness of San Isabel National Forest, 10.6 miles (17.1 km) west-southwest (bearing 247°) of the City of Leadville in Lake County, Colorado, United States.