West of Vernal and northwest of Roosevelt, the Yellowstone ATV Trailhead provides access to two loops: Petty Mountain Loop (14 miles) and Dry Gulch Loop (32 miles)..
To reach the trailhead from Roosevelt, travel north along UT 87 to Mountain Home, then north to Yellowstone along FR 119. A parking lot and trailhead are located in the lower Hells Canyon area just past the Ashley National Forest boundary. The trail begins in the lower Hells Canyon area of Yellowstone Canyon, along FR 119. At its junction with FR 196, head west along a good dirt road. Continue along FR 196 as it climbs and winds its way towards Petty Mountain. Pedal across Flea Flat and through Bear Park. There is a spur there to Lake Fork Mountain. At Mill Park, the trail bends northeast and intersects FR 227 at Mill Spring. Take a right onto FR 227 and head southeast down through Hells Canyon back to the trailhead.
Note: As of September 2007, ATV riding on Forest Service roads requires a Utah ATV registration. Only certain designated Forest Service roads are open to ATV riding.
Overall, Yellowstone ATV Trailhead is the 16th most popular ATV riding trail of all 75 ATV trails in Utah.