Thunder Gulch Trail

Thunder Gulch Trail is a signed out-and-back on Eastern Head that ends at a narrow cleft in the rocky coast, with the open sea beyond. From the signed access, allow about 1.6 miles round trip—roughly 0.8 mile each way—and about 1.5 hours for the walk and a careful stop at the shore. It is a good choice if you want a short, unusual coastal walk on Isle au Haut; the route is rougher and less straightforward than its distance suggests.

The trail is absent from the park’s published island map, and accounts describe a residential dirt-road approach that passes close to homes. The route itself is mapped as a designated, NPS-operated footpath, but current public rights along the approach and a public parking place could not be confirmed. Follow only clear public trail signs; do not enter private yards or driveways, and turn back if the way is not plainly marked.

The walk begins along the residential approach, then crosses open, wind-exposed ground with low trees. Reports describe downed wood, intermittent blazes and side paths toward the shore, so stay on the signed route instead of following an attractive but uncertain opening. Expect uneven ground rather than a smooth stroll.

Thunder Gulch is a deep, narrow break in the coastal rock, with waves moving through the gap and an open ocean view from the stony point nearby. The sound and force of the surf vary with the tide and sea. Keep to stable rock well back from the steep edge; scrambling closer adds risk without improving the view. A good photo frames the dark cleft with the strip of open water beyond.

Isle au Haut is reached by passenger ferry from Stonington. Services on the island are limited; a small store and post office are near Town Landing, not at the trail, and hours are limited. No trailhead food, water, restroom or confirmed parking was found, so arrange supplies and access before setting out. Dogs are allowed on park trails on a leash no longer than six feet.