Campsites at Three Mile Campground (20226 Guide)

What makes a campground three miles from the nearest trailhead worth the trek? For Isle Royale visitors, Three Mile Campground answers that with a simple proposition: you can get to it by boat or on foot, and it sits just far enough from Rock Harbor to feel like you've left civilization behind without committing to a full day of hiking.

This guide covers everything you need to know about camping at Three Mile for the 2026 season - site types, access options, fees, and the new food storage rules that changed how you pack for the east end of the island.

Location and Access

Three Mile Campground sits on the Rock Harbor Channel, accessible via both the Rock Harbor Trail and the Mount Franklin Trail. It's about three miles from the Rock Harbor visitor center - hence the name. The dock has a depth of 9 feet under normal conditions, which matters more than most first-time visitors realize because shallower docks elsewhere on the island can be tricky for larger private boats.

You have three ways to reach it:

• On foot: The Rock Harbor Trail runs flat along the shoreline. It's an easy hour-or-so walk from Rock Harbor Lodge.
• By canoe or kayak: The channel provides protected water most days, though wind can pick up in the afternoon.
• By private boat: The dock can accommodate overnight docking, but remember the 9-foot depth - if you draw more than that, you'll need to anchor out.

The campground is open from April 16 through October 31 annually, 24 hours a day. That matches the park operating season. Outside those dates, the island effectively shuts down, and you'll find no services, no rangers, and no ferry access.

Campsites and Reservations

The site inventory breaks down like this: 8 shelters, 4 tent-only sites, and 3 group sites - 15 total. Shelters offer three-sided wooden structures with a roof and a raised floor. They're popular for good reason: they block wind and keep rain off your gear. Tent-only sites are just that - cleared pads where you pitch your own tent.

Small-Party Camping (6 people or less)

No fee. Zero. A free overnight permit is required, which you get at the visitor center or a backcountry permit station. It's first-come, first-served, which means you cannot call ahead or reserve a shelter for your small group. Rangers will tell you that the shelters fill early - by 2 PM on summer weekends, expect them gone.

Group Sites (7 or more people)

All parties of 7 or more must use the group sites and submit a group permit request through the park's online system. The fee is $25 per permit (not per person). These are advanced reservation only - you cannot show up with a group and expect to walk into a site.

Stay Limit

From June 1 through September 17, you are limited to one night. This prevents people from squatting at the most convenient campground along the Rock Harbor trail. Outside that window (spring and late fall), the limit may be relaxed, but check the current conditions at the visitor center.

The New Food Storage Guidelines

As of 2026, the park has implemented stricter food storage guidelines specifically for Rock Harbor and campgrounds on the east end, including Three Mile. The reason: wolves have accessed human food and garbage in the area.

This is not a hypothetical warning. Wolves on Isle Royale have learned that campsites sometimes contain easy calories. Once that happens, the behavior spreads. The park's response includes:

• All food, cooking gear, and scented items must be stored in provided food lockers or hung properly. Shelters have lockers. Tent sites require you to bring your own bear-resistant container or hang your food.
• Cooking and eating should happen at least 100 feet from where you sleep.
• Garbage must be packed out completely. There is no trash service at Three Mile.

What the park website doesn't mention in bold letters: this rule applies to toothpaste, sunscreen, lip balm, and any wrappers. If it smells like something edible or has touched food, it goes in the locker. Most visitors underestimate how many scented items they carry.

What to Expect When You Arrive

The trail narrows here. Approaching from Rock Harbor, you'll cross a small bridge over a creek before the campground opens up on your left. The shelters face the channel, and on calm mornings you can hear water lapping against the dock.

Early morning is your best bet for spotting wildlife along the shoreline. Loons call across the water, and moose occasionally wade in the shallows. Keep an eye out for beaver activity in the coves - their lodges are visible from the trail.

Cell service drops out about half a mile from Rock Harbor. You'll have no signal at Three Mile. The pay phone at Rock Harbor Lodge is your only connection to the outside world once you leave the developed area.

The dock itself is functional but not fancy. It's a floating dock that rises and falls with water levels. Private boaters tie up to the cleats. Canoeists and kayakers can pull up onto the gravel beach nearby.

Practical Takeaways

1. Arrive early. Shelters go first. If you're hiking in from Rock Harbor, start before 9 AM to have a good shot at one. By mid-afternoon, expect to be using a tent site.
2. Bring a bear canister if tent camping. The food lockers are for shelter users only. Tent sites have poles for hanging food, but a canister is more reliable and saves you the hassle of finding a good tree.
3. Pack for one night, maybe two. The one-night limit from June 1 to September 17 means you can't settle in. Plan your route to move on to Lane Cove or Daisy Farm the next day.
4. Check the weather forecast at Rock Harbor. The channel can get choppy. If you're paddling, a north wind makes the crossing uncomfortable. Wait it out if needed.
5. Respect the wolf food storage rules. This isn't about protecting your snacks - it's about preventing habituation that leads to problem animals being euthanized. Rangers are serious about compliance.

Final Thoughts

Three Mile Campground doesn't offer solitude. It's the closest backcountry site to Rock Harbor, which means it sees steady traffic through the season. But it serves a specific purpose: it's the first step into Isle Royale's interior for hikers and a quick overnight for boaters who want to stretch their legs onshore.

The one-night limit forces you to keep moving, which is exactly what a place like Isle Royale demands. You wouldn't come here to sit still. Pack your food properly, grab a shelter if you can, and use Three Mile as the launching point for a longer trip into the island's backcountry.

For a full run-down of everything this campground offers - including trail connections and packing lists - see our complete visitor guide. If you're comparing options across the island, we've also listed it alongside neighboring sites in our all campgrounds resource.