The Lonesome Bachelor is a summit in Ravalli County, Montana, United States.

The Lonesome Bachelor is part of the Bitterroot Range which is a subrange of the Rocky Mountains.

Topographic relief is significant as the summit rises approximately 2,200 feet (671 meters) above headwaters of Little Rock Creek in 0.5 miles (0.80 km).

This mountain's toponym has been officially adopted by the United States Board on Geographic Names.

This Ravalli County, Montana state location article is a stub.