One of the shortest approaches to any 12,000-foot summit in the Beartooths, making Spirit Mountain one of the few in the range that's a realistic one-day round trip.
From the Rock Creek Trailhead (Main Fork), at the Montana/Wyoming border, a steep switchbacking trail through an old burn area leads to a footbridge over Rock Creek, then continues up a valley dotted with numerous lakes. The route leaves the trail to climb a moderate-angle snow slope on Spirit Mountain's south side, finishing on easier ground to the summit, where the remains of a historic benchmark plaque once sat.