West of St. Mary in Glacier National Park, the popular 20 mile Gunsight Pass Trail passes more glaciers than any other hiking trail in the park. It starts from the Jackson Glacier Overlook west of St. Marys on Going-To-The-Sun Road. It descends down to and follows St. Mary River climbing back up to Gunsight Lake and Gunsight Pass. Next, it follows the headwall of Lincoln Creek Valley past Lake Ellen Wilson, and then over Lincoln Pass. Stop at the Sperry Chalet for a rest (overnight accommodations typically require booking in January). Head up the spur trail to the Sperry Glacier (7.4 mi round trip). Afterwards, continue on the Gunsight Pass Trail down into the Sprague Creek Valley and on to Lake McDonald.
Overall, Gunsight Pass is the 14th most popular hiking trail of all 19 hikes in Montana.