Big Horn Mine Hiking Guide
Big Horn Mine delivers one of the most striking human-made sights in the San Gabriels: a weathered timber stamp mill clinging to a steep slope high above the East Fork drainage, still standing after more than a century of winters. The route from Vincent Gap follows an old mining road that stays close to level for most of its length, which makes this an unusually accessible hike for the high country. Do not let the gentle grade fool you into ignoring the elevation — the trailhead sits near 6,500 feet.
Starting at Vincent Gap
The trailhead is the large Vincent Gap parking area on Angeles Crest Highway, the same lot used by hikers heading up Mt Baden-Powell. An Adventure Pass or equivalent federal pass is required. The Big Horn Mine trail leaves from the west side of the lot, immediately splitting off from the Pacific Crest Trail — take the old road grade contouring right rather than the switchbacks climbing left. This junction is where most people go wrong. Vault toilets are available at the lot, which is worth knowing on a road with few facilities.
A Rare Nearly Level Trail
The route follows the bed of an old mining road, which means it was graded for wagons rather than for hikers, and it contours around the mountainside with very little net gain. You pass through mixed conifer forest, cross a few gullies, and get intermittent views down into the enormous East Fork canyon. The tread is generally good, though a couple of spots have eroded into narrow traverses with real exposure below. Those sections are short and manageable for anyone comfortable with heights, but they are not the place for an off-leash dog or a distracted child.
The Mine Itself
The stamp mill is genuinely impressive — a multi-story wooden structure built into the slope, with rusted machinery and tailings spilling below. It photographs beautifully in morning light. The structure is old, unmaintained, and unstable, and the adits nearby are dangerous. Mine shafts in the San Gabriels have killed people; they hold bad air, hidden vertical drops, and rotten timbers. Look, photograph, and stay outside. The ground around the mill is loose tailings that slide easily, so watch your footing while you are gawking at the view.
Seasons and the Highway Question
The big planning variable here is not the trail but Angeles Crest Highway. State Route 2 closes seasonally through the high country, and when the gate is shut, Vincent Gap simply is not reachable from that direction. Always check current highway status before driving. When the road is open, late spring through fall is prime, with wildflowers in early summer and crisp air with golden aspens in October. Winter brings snow that makes the exposed traverses genuinely dangerous without traction gear.
Altitude and Preparation
At roughly 6,500 feet, the trailhead is high enough that hikers coming up from the Inland Empire or the coast will feel it, particularly in the first mile. The nearly flat profile disguises this — people push a fast pace because the trail is easy, then wonder why they are winded. Carry more water than the mileage suggests, since the dry high-country air pulls moisture fast, and bring a windproof layer even in summer. Afternoon thunderstorms build over these ridges in July and August; be heading back by early afternoon.
Hiking tips for Big Horn Mine
- Check the status of Angeles Crest Highway before you drive — seasonal closures on SR-2 make Vincent Gap unreachable for months at a time.
- At the trailhead take the contouring road grade to the right, not the PCT switchbacks climbing left; that junction is where most people lose the route.
- Stay outside the mine adits without exception — bad air, hidden shafts, and rotten timbers have killed people in San Gabriel mines.
- Pace yourself in the first mile despite the flat profile; at roughly 6,500 feet the altitude catches out hikers arriving from the valley.
- Turn around by early afternoon in July and August, when thunderstorms build fast over the ridge and the exposed traverses offer no shelter.
Nearby trails to explore
- Mt Baden-Powell
- Lightning Ridge Nature Trail
- East Fork San Gabriel River
Hike this trail with TrailMates
Big Horn Mine is a high-country hike with an easy grade and a genuinely memorable destination. Use TrailMates to find hikers coordinating Angeles Crest trips around the seasonal road closures, and carpool up together rather than driving the long way alone. Download the TrailMates app to join a group.