If you're wondering how to fit all the best of Glacier National Park into one backpacking trip, Gunsight Pass may be the answer you're looking for. The trails and campsites between Jackson Glacier Overlook and Lake McDonald link deep woods, idyllic streams, picturesque waterfalls, pristine lakes, high peaks, huge glaciers, proud vistas, and plentiful wildlife. A one- or two-night trek is the best way, but it can also be done as a very long day hike.
Gunsight Pass is on the saddle between Gunsight Mountain and Mount Jackson. The Gunsight Pass Trail begins at Jackson Glacier Overlook on Going-to-the-Sun Road and goes generally southwest, climbing more than 3,000 feet in 9.2 miles to reach the pass. From there the trail continues generally west, down to Lake Ellen Wilson and eventually linking with Sperry Trail at Sperry Chalet. The distance from Gunsight Pass to the Sperry Trailhead at Lake McDonald is approximately 11 miles.
Many spur trails along the way make worthwhile side hikes if you have the time and energy. These include: St. Mary Falls, Florence Falls, Jackson Glacier, Sperry Glacier, Gunsight Mountain, Snyder Lakes, and Mount Brown Lookout.
All backcountry camping requires permits, which are reservable in advance online. They are alternatively available in person at the backcountry office the day before or day of your hike. Either way, the number of permits is limited, and sites along this route usually fill up very quickly. The campgrounds from east to west are Reynolds Creek, Gunsight Lake, Lake Ellen Wilson, and Sperry. For more information, visit the national park's backcountry camping webpage.
Lodging at Sperry Chalet has been a very popular option in the past. Sadly, the Sprague fire destroyed the dormitory building in 2017, but plans to rebuild this historic structure are underway. Be sure to check in for updates before you start your hike.
You can begin the hike from either end. Out-and-backs of any distance along the route are worthwhile, but because Gunsight Pass is approximately halfway between the two starting points, you will get far more bang for your buck by doing it as a thru-hike. This is made easy by the park's free shuttles along Going-to-the-Sun Road: You can leave your car at either end and catch a ride. Parking is much more plentiful at Lake McDonald Lodge on the hike's west end than at Jackson Glacier Overlook on the east end. Just be sure to check the shuttle schedule so you know when the first and last buses run.