Tobin–Duncan Portage Trail

Tobin–Duncan Portage is a 1.6-mile out-and-back over Greenstone Ridge between Tobin Harbor and Duncan Bay. Paddle to the Tobin Harbor portage marker, climb steeply to the ridge, descend to Duncan Bay, then retrace the same path to your vessel. The park map’s 0.8 mile is one way; its 175-foot gain describes the crossing, and you climb over the ridge again on the return.

This is a short walk with a serious grade, not a casual shoreline stroll. Allow about 1½ hours on foot, plus the separate paddle to and from the marker. That time is a practical estimate; the park gives no walking time.

Access the portage by water, not from a road parking area. From Tobin Harbor Dock, paddle directly across Tobin Harbor to find the Tobin/Duncan Portage marker. The mapped marker point is approximate, so use the on-the-ground portage marker. The hike ends at Duncan Bay, but this outing turns back to the boat rather than continuing to another road or dock.

Bring water and rain gear, as the park advises for day hikes here. Paddle time is not included in the hiking distance or estimate.

The park map rates this crossing extremely steep. The hard part is climbing to the ridge, descending toward Duncan Bay, and doing that climb again on the way back. Trails can be slippery when wet, so rain can make the short route feel more demanding.

Pets are not allowed on Isle Royale. Service dogs require a park permit arranged before the trip.