mountain segment of the northern Rocky Mountains, in northwestern Wyoming and southern Montana, U.S. Extending in a northwest-southeast direction, the range is 170 miles (270 km) long and 50 miles wide. A large plateau, the result of volcanic action, was uplifted in the area, and stream and glacial erosion have produced spectacular features. Eight summits exceed 12,000 feet (3,700 m), including Francs Peak (13,140 feet), the highest point. The range is a source for headstreams of the Bighorn River and embraces portions of the Gallatin, Shoshone, and Custer national forests and the extreme northeastern part of Yellowstone National Park. Granite Peak (12,799 feet), the highest point in Montana, is in the Beartooth Range, a northeastern spur of the Absarokas.