Falls River Basin Trail is a 15.8 mile moderately trafficked loop trail located near Yellowstone National Park, Wyoming that features a lake and is rated as moderate. The trail is primarily used for hiking, trail running, camping, and backpacking and is best used from May until September.
Directions from Flagg Ranch or Ashton Idaho: The route in from Flagg Ranch is more scenic and rougher. Flagg Ranch is located just south of the park on the Ashton-Flagg road, past Grassy Lake Reservoir. Watch for a signed junction, turn right toward Cave Falls Road and right again onto Cave Falls Road. Continue about 2 miles to a junction where the pavement starts, turn left here to reach the trailhead at the ranger station. Allow 2.5 hours from Flagg Ranch.To get to the Ranger Station/ Trailhead from the west, either Ashton Idaho or West Yellowstone, take Idaho Highway 47 . Follow this highway to Green Timber Road, which turns into Cave Falls Road. Allow 1 hour from Ashton, Idaho a distance of 22 miles.