Isle Royale Greenstone Ridge Trail

Isle Royale National Park (Windigo to Rock Harbor)

Check before you go. Check before you go: on Aug. 28, 2026, the National Park Service closed tent sites, group sites, hammock use, and the nearby off-trail camping zones at Three Mile, Daisy Farm, Moskey Basin, and Caribou Island because wolves were pawing at tents and dragging off packs and sleeping pads. The closure runs through the park's Oct. 31 seasonal close; the 32 shelters at those campgrounds stay open. The NPS current-conditions page (updated Sept. 30, 2026) says the Greenstone Ridge Trail between Daisy Farm and East Chickenbone campgrounds is flooded by beaver activity, with a flagged reroute north of the trail that rejoins it near the west end of Angleworm Lake. It lists off-trail camping zones 9 through 13 and 30 through 38 as closed, Merritt Lane Campground as open, and the Red Rocks Fire (July 2026, near Tobin Harbor) as 100% contained. The park is open April 16 through Oct. 31 and closed Nov. 1 to April 15, and the NPS says ferries and the seaplane run from mid-May through September.

The Greenstone Ridge Trail runs the length of Isle Royale, an island in Lake Superior that is reached only by boat or seaplane. The National Park Service calls it the island’s longest trail, about 41.7 miles from Windigo at the southwest end to the northeast end near Rock Harbor.

There is no road to either end. Backpackers ride a ferry or seaplane in, carry a free permit, and camp at first-come, first-served campgrounds along the way.

The hike

The NPS lists two trailheads: Windigo, reached by ferry, seaplane, or private boat, and Hidden Lake, reached by private boat or water taxi from Rock Harbor Lodge. Backpacker (2013) says most hikers go east to west, while BackpackingRoutes lays out a five-day eastbound itinerary from Windigo.

From the east, the NPS breaks the trail into sections: Lookout Louise to Mount Franklin (about 5 miles), Mount Franklin to Mount Ojibway (2.8), Mount Ojibway to Chickenbone Lake (5.7), Chickenbone Lake to Hatchet Lake (7.2), Hatchet Lake to Ishpeming Tower (3.8), Ishpeming Tower to South Desor (3.5), South Desor to Island Mine (5.2), and Island Mine to Windigo (6.5). Backpacker’s writer urges hikers not to skip the first stretch: “Most GRT hikers skip the five miles from Lookout Louise to Mt. Franklin. Big mistake.”

Backpacker notes lookout towers at Ishpeming Point and Mount Ojibway. BackpackingRoutes puts the high point at Mount Desor, 1,394 feet, with about 4,000 feet of total climbing and little that is steep for long. Near the western end, Backpacker mentions a prehistoric mine site and Monument Rock.

The NPS describes the tread as about 18 inches wide, with rocks, roots, wooden plank bridges, and steep inclines, and says no potable water is available along the trail. BackpackingRoutes adds that water is scarce on the ridge itself, so hikers carry each day’s supply or detour to inland lakes and creeks.

The NPS lists these campgrounds along the route: Washington Creek, Island Mine, South Lake Desor, Hatchet Lake, West Chickenbone, East Chickenbone, Daisy Farm, Three Mile, and Rock Harbor. BackpackingRoutes suggests leaving the ridge at Mount Franklin to end at Three Mile and Rock Harbor, which makes a short last day.

The park says backpackers usually cover six to eight miles a day. For the island’s harder and shorter routes, see the Minong Ridge Trail and the Feldtmann Loop.

Tips

Plan for wolves. In 2026 the NPS closed tent camping at four east-end campgrounds after wolves damaged tents and took gear. Store food and packs as rangers direct.
Carry water capacity. The ridge is dry for long stretches.
Build in a weather day. Boats and seaplanes depend on Lake Superior conditions.
Go late summer for fewer bugs. BackpackingRoutes says mosquitoes and black flies peak in July; Backpacker suggests mid-August through September.
Bring stove fuel by boat. Seaplane passengers can buy fuel on the island (NPS).

Camping

Parties of one to six need a small-party permit, but the NPS says there is no need to apply ahead: a ranger issues it aboard the Ranger III or on arrival at Windigo or Rock Harbor, and seaplane passengers self-permit. Display it on your pack while hiking and on your tent or shelter in camp. Campgrounds are first come, first served. Groups of seven or more need advance group reservations.

Consecutive-night limits apply from June 1 through Labor Day (through Sept. 21 at Rock Harbor, Three Mile, Lane Cove, and Washington Creek). If a campground is full, the NPS says to use the overflow group site, share a tent site, or pitch outside a shelter; off-trail camping needs a permit addendum. Fires are allowed only in designated metal rings or standing grills. The NPS says to filter and chemically treat backcountry water; potable water at Rock Harbor and Windigo typically runs from late May to mid-September.

Inside Intel: BackpackingRoutes’ writer singles out Three Mile, whose rocky shoreline is “washed by the surf all day and brilliant with starlight all night,” and says “Don’t miss it.” Its tent sites are closed for the rest of 2026, though its shelters remain open.

Trail facts

Distance: About 41.7 miles (NPS); over 40 with spurs (NPS trip page)
Route type: Point to point, Windigo to Hidden Lake or Rock Harbor
Difficulty: Moderate to strenuous
Campgrounds: Washington Creek, Island Mine, South Lake Desor, Hatchet Lake, West and East Chickenbone, Daisy Farm, Three Mile, Rock Harbor
Water: None potable on the trail; filter and treat
Permits: Free small-party permit (1-6); group reservations for 7+
Pets: Not allowed (NPS trip pages)
Access: Ferry, seaplane, or private boat; park closed Nov. 1 to April 15
Last verified: October 17, 2026

The Lowdown

Pitching beside a full shelter on the Greenstone:

When ridge campgrounds fill in midsummer, the park lets late arrivals pitch a tent outside a shelter. See the backpacking tents reviewers trust.

Read the full guide →

Where this comes from

This page draws on the sources below, along with other guides and trip reports. Links go to the original pages.

Before you go: This page is based on published trail guides, trip reports, and reviews, along with official park and agency information where we could find it. It’s meant to help backpackers discover new trails, not to replace current, official information. Conditions, closures, permits, campsites, and water sources change, and some details here may be out of date or wrong. Confirm everything with the managing agency and check current conditions before you head out, and don’t rely on this page alone for safety or navigation. Backcountry travel involves risk.