Mount Lebanon is a 5,807-foot (1,770-metre) mountain summit in Liberty County, Montana, United States.

[1] Topographic relief is modest as the summit rises over 1,500 feet (460 meters) above the surrounding plains in one mile.

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

[3] Mount Lebanon is an exposed laccolith composed of diorite porphyry which was created by an igneous intrusion through older Cretaceous sedimentary rocks during the Eocene, about 50 million years ago.

[4][5] Over time, erosion of the sedimentary rock has exposed the solidified laccolith which is more resistant to weathering.