Suzy’s Cave Loop

From the trail access just past Rock Harbor Campground, follow Rock Harbor Trail west. The park places the cave turnoff about 1.8 miles beyond the campground. The tread is unpaved, narrow, and covered with rocks and roots; the park says this is significantly more challenging than Tobin Harbor Trail. Watch for the wooden post and take the inland connection to the cave rather than continuing along the longer routes toward Three Mile.

Suzy’s Cave is a small opening beneath a broad rock arch, not a cavern to walk through. Waves cut the arch when Lake Superior stood higher, about 4,000 years ago; the old waterline now sits inland from today’s shore. The NPS natural-history handbook links it to the Lake Nipissing stage, when the lake stood about 40–60 feet above its present level. The rock makes a brief stop feel like a glimpse of a different lake edge. For a photo, include the stone lip and dark opening together, with some of the rocky approach in view so the arch’s shape reads clearly.

From the cave, continue to Tobin Harbor Trail and follow its gentler tread back to Rock Harbor. This is the easier half of the circuit, but it remains an unpaved forest path. Walkers describe water views along both sides, so the return gives you a different look at the harbor rather than simply repeating the same shoreline. If the Rock Harbor tread is too rough, the park also identifies Tobin Harbor Trail as an alternate way to reach the cave; walking that trail out and back avoids the rougher leg, but means retracing the easier side instead of making the loop. Spruce, fir, and birch form a thick canopy through much of the walk. Moose are among the wildlife the park suggests watching for, though sightings are never guaranteed.

Rock Harbor is reached by ferry, seaplane, or private boat; there is no road access or parking on Isle Royale. The route is listed for spring through fall, and dogs are not allowed. Carry drinking water: seasonal potable water is available in Rock Harbor, but I found no confirmed refill point on the trail. The Greenstone Grill and Lighthouse Restaurant are separate, seasonal food stops back in the Rock Harbor area; service dates vary. Wet trails can be slippery, especially on the rockier Rock Harbor leg.