Take Going-to-the-sun road in Glacier National Park until you reach the Avalanche Trail parking lot. About 16 miles.
The Avalanche Trail is one of the most popular trails in Glacier National Park. With it's boardwalk through 100 year old pines and the Avalanche Gorge, makes it accessible to everyone. Taking the trail further up, off the boardwalk, you walk along side the the gorge with it's massive water flow through bowls that have been carved out for hundreds of years. The trail takes you to Avalanche Lake which is a sight that is well worth the hike.