Starting at the Warm River Campground, this trail offers wonderful vistas and differing ground types from gravel to asphalt to dirt. It meanders with the river holding to a gentle elevation gain.
Tunnel Near Warm River
The tunnel near warm river originally had a railroad passing through it. A passenger train departed from Ashton, Idaho for West Yellowstone, Montana in June of 1908, but was delayed by a day because of a landslide. In response to this landslide, this 557 foot tunnel was constructed in 1915 to prevent future delays caused by landslides that frequented the area. This can be found close to an additional parking lot (44.151882, -111.285866). If you are only seeking to see the tunnel, park at this location and safely cross the highway. Then, follow the trail north until you find the tunnel.
The tunnel suffered a cave-in 2008 so access is prohibited.
The rest of the trail
Continuing the rest of the trail, you can reach west Yellowstone. It would take around a day for a full round trip. The trail totals 39 miles round trip. There are smaller branches to the main trail. Expect to travel through beautiful pine and fir forests. Springs and creeks can be found throughout the trail.Free