Fossil Mountain (10,921 feet (3,329 m)) is located in the Teton Range, within the Jedediah Smith Wilderness of Caribou-Targhee National Forest, U.S. state of Wyoming.

[3] As mapped by J. D. Love and others, the peak of Fossil Mountain consists of relatively flat-lying beds of the Mississippian Madison Limestone and underlying Devonian Darby Formation.

In all, there is about 2,700 feet (820 m) of lower and middle Paleozoic sedimentary strata exposed within the area of Fossil Mountain.

[8][9][10] Fossil Mountain Ice Cave has a combination of hazards that have resulted in frequent rescues.

[8][9][10] The analysis of measurements of stable isotopes of oxygen and hydrogen recovered form samples of ice collected from Fossil Mountain Ice Cave provided a record of paleotemperatures of this part of the Teton Range for the past 175 years.