Klamath National Forest · California
Trailhead East Boulder Trailhead Drive there
Trailhead is up Forest Road #39N10 from Road 40N17 out of Callahan.
Trail #5575 leaves the trailhead going south towards Lower Boulder Lake Falls and East Boulder Lake in the Trinity Alps Wilderness. Passing the lake, the trail connects to the Pacific Crest Trail in the Shasta-Trinity National Forest.
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.