Montana's Marias Pass is the lowest rail crossing through the Rocky Mountains. The tracks snake through narrow canyons, traverse the swift Middle Fork of the Flathead River, and twist through numerous snowsheds and tunnels to crest the 5,213-foot Continental Divide. James Jerome Hill was the driving force behind Great Northern Railway's mission to find the most economical route to the Pacific coast, with surveyor John F. Stevens taking a major role in locating the pass. Browning is the eastern gateway into Marias Pass as the railroad approaches the Rocky Mountain Front; continuing west from Summit, the tracks parallel Bear Creek and the Middle Fork of the Flathead River downgrade through Essex to Glacier National Park and into the Flathead Valley.