Middle Fork Trail #4001 is a 78-mile wilderness trail that parallels the Middle Fork Salmon River through the Frank Church-River of No Return Wilderness, beginning at the Middle Fork Transfer Camp & Trailhead near Boundary Creek.

The trailhead offers toilet facilities, stock holding facilities, and a ramp, with long-term parking available for boaters.

Users should be prepared for challenging terrain with elevation changes, potential rockfall and downed trees, spring flooding, and wilderness regulations including Leave No Trace ethics; a saw and shovel are recommended, and cellphone service is unavailable.