2.5 mi of trail, end to end · about 70 ft of climbing · 650 ft of descent · 7,879 ft–8,498 ft · native material surface · trail No. 2725 · trail class 4 · typical grade 8-10% · tread 24-36 inches wide · hiking, bike
TrailheadMammoth Rock Trailhead 8,501 ft Drive there
Mammoth Rock Trailhead the Forest Service's write-up
2.5 miles
Intermediate
This trail follows an old jeep road, then turns to single-track, climbing up a forested slope before reaching a clearing caused by an avalanche in 1986. The trail then passes below Mammoth Rock, a massive limestone and marble monolith containing fossils estimated to be 250 million years old. Continue to the end of the trail, which intersects Old mammoth Road.
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.
