ApproachFrom Highway 395 in Bishop, head west on Highway 168 for about 7 miles, then turn right and follow Buttermilk Road for about 9 miles until the road becomes too crummy to drive on anymore. A high clearance or four wheel drive vehicle is needed to get reasonably close to the trailhead. From the Horton Lakes trailhead, follow the trail, which is really a four-wheel drive road, for 3.5 miles until lower Horton Lake at 10,000 feet is reached. This is a lovely area. Turn north (right) and follow a road that switchbacks up a hillside until the top of the hill is reached at 11,600 feet and the terrain and trail flatten somewhat. Mt. Tom is in view once again. For the next mile, the trail traverses the side of the mountain.
Route DescriptionAfter reaching the Tungstar Mine, follow a use trail up a chute for the next 500 feet. Eventually, the trail disappears and the scree-talus slog begins, although the slog is actually not too bad of a slog, as far as slogs go. Continue up, crossing over a rib, then another chute, then another rib, and head to the summit. Although it’s not a glorious climb, the view is outstanding, and on a clear day includes much of the Sierra Crest from Mt. Whitney to Mt. Dana.
A More Interesting Third Class VariationCrag adds:
An overhanging cornice forms along the crest of the SW ridge. This cornice can be seen pretty clearly with binoculars from the 4 Jeffrey campground. In 2003 it remained in place through at least mid-June.
The crest of the SW ridge can be followed from where the abandoned mining road tops the ridge, all the way to the summit. This involves some ups and downs over 3rd class rock.