Elevation: 5,495 ft.
Length: 9.4 miles
The Flattop Mountain Trail begins at Packer's Roost, which is a trailhead and old cabin, on a short spur road, off the Going-to-the-Sun Highway and located 23 miles east of West Glacier.
This trail follows the McDonald Creek valley up to the crossing of Mineral Creek, where it turns north towards Flattop Creek. It is an interesting 5.7 mile hike to the Flattop Mountain Campground and then again 6.3 miles further from this campground to Fifty Mountain Campground if you were interested.