NE Entrance Rd, Yellowstone National Park, WY 82190, USA | Meet at the Lamar River Trailhead (Hiker Trailhead, not Stock Trailhead.)
From Gardiner, MT / Tower Junction: The trailhead is 14.8 miles from Tower Junction (25 minutes). Turn onto Highway 212 at Tower Junction toward Cooke City. After driving through the Lamar Valley you will pass the Lamar River Stock Trailhead. This trailhead is for horse users. There are two latrines at this location. This is your last civilized bathroom location. The hiker trailhead is another 0.25 mile upstream. This large parking lot for the Lamar River Trail has no latrines. If you get out of your vehicle you will see a small footbridge.
From Cooke City, MT: The trailhead is 18.3 miles from Cooke City (30 minutes). It is located approximately 0.5 mile past the small, white Soda Butte thermal formation.