Custer Gallatin National Forest · Montana
Trailhead Twin Cabin Trailhead Drive there
Developed trailhead with horse ramp, picnic table, and toilet. Twin Cabin trail ties into the Porcupine Trail after about two miles.
Trail is closed to all motorized use.
The lines are the US Forest Service's National Forest System trails layer (public domain), read 2026-10-16 and simplified for the map; the length is the line's, end to end, and the class, surface, grade and tread width are the forest's own entries where it publishes them - a forest that publishes the centreline alone has none. The trailheads and the points along the way are the Service's recreation points, and the write-ups its own recarea text, unedited. Heights come from USGS 3DEP through Terrain Tiles on AWS (Mapzen/Tilezen), read along each line and rounded; a short trail on steep ground can be off by a few tens of feet. Closures change: check the forest's own site before you go.