The North Entrance Road from Gardiner, Montana, to Mammoth Hot Springs, Wyoming, runs along the Gardner River. The road winds into the park, up the canyon, past crumbling walls of sandstone and ancient mudflows. The vegetation is much thicker in the canyon than on the open prairie down below, the common trees being Rocky Mountain juniper, cottonwood, and Douglas-fir. Low-growing willows also crowd the river's edge in the flatter, flood-prone sections of the canyon. Watch for wildlife in season: eagles, osprey, dippers, and kingfishers along the river and bighorn sheep in the steeper parts of the canyon.