Part of The US National Parks
- Where
- Lake Superior, Michigan
ferry or seaplane only - Coordinates
- 48.0000° N
88.9000° W - Biome
- Boreal island wilderness
- The study
- Wolves & moose counted
annually since 1958 - Status
- 99% designated wilderness
UNESCO Biosphere Reserve - Best visited
- Mid-June–September
There is a ledger on this island older than my list, kept by people who count wolves and moose the way I count items — every year, without fail, in every weather. I have enormous respect for anyone who refuses to stop counting. I added three items on the crossing alone. The lake had opinions about my hat.
The short answer
Isle Royale is a wilderness archipelago in the northwest of Lake Superior, protected as a US national park and reachable only by ferry or seaplane. Ninety-nine per cent of it is designated wilderness. It is best known for the Isle Royale wolf–moose project, the longest continuous study of any predator–prey system in the world, running every year since 1958. It is routinely among the least visited national parks in the United States — and it is the rare one that closes entirely for winter.
Why it's worth knowing
Most ecosystems are impossible to study cleanly because too much is happening at once. Isle Royale is nature with the variables removed: an island where wolves are the only predator of moose, and moose are essentially the only food for wolves. No bears, no deer, no hunting, no roads. The researchers themselves make the point plainly — if we cannot understand the simple places, that says something about our chances with the complicated ones.
Neither animal is ancient here. The moose are believed to have arrived around 1900, apparently by swimming from the mainland. The wolves walked — across an ice bridge from Canada in the late 1940s. The whole drama is barely a century old, played out on a stage that froze into place around it.
The field notes
The longest ledger in ecology
The study began in 1958 as a ten-year project under Durward Allen of Purdue University. It never stopped. Now led from Michigan Technological University, it entered its 68th consecutive year in 2026, making it the longest continuous predator–prey study anywhere.
The numbers swing hard. Since 1980 the moose population has ranged from roughly 500 to 2,400; wolves have been as many as 50. What moves them is everything from winter severity to disease to the growth rate of balsam fir, the moose's staple winter food — and the record is long enough that patterns invisible in any single decade become legible across six.
Down to two, and back
The wolves nearly vanished twice over. A canine virus reached the island in the early 1980s and crashed the population; then a warming climate began robbing the lake of the ice bridges that had let new wolves — and new genes — cross from the mainland. By 2018 the island held just two wolves, closely related and heavily inbred.
So the National Park Service intervened, translocating wolves from Minnesota, Ontario and Michigan's mainland in 2018 and 2019 to restart the population. It worked. Counts reported in 2026 put wolves near their highest numbers in almost fifty years, with moose correspondingly low — the seesaw tipping back within its historic range. Whether managers should intervene in a designated wilderness at all was genuinely argued, and the ledger is how anyone will ever know what the intervention did.
An island that closes
Isle Royale closes completely from November through mid-April — the rare US national park that shuts for the season, because Lake Superior in winter is not a place for scheduled ferry service. The one regular exception is the study itself: the winter count, conducted from a small aircraft over the frozen island, is how the wolf and moose totals have been taken since the beginning.
The rest of the year, the island belongs to backpackers, paddlers and the passengers of a few ferries. Loons call on the inland lakes at night. Visitor numbers that other parks record in a day, Isle Royale records in a year — and the people who do come stay days, not hours.
- Hear a loon across still water — once by accident, once on purpose.
- Find a moose print and stand beside it. Beside, not in. Manners.
- Treat the ferry as an expedition. (It is one.)
- Ask the counters what number they are on, and admire it without writing it down.
- Stay one extra day. (Approved by the list committee, which is me.)
A moose skeleton, catalogued. For decades the project has enlisted volunteers to comb the island for the bones of moose, each find measured, numbered and added to a research collection now spanning thousands of animals — arthritis, injuries and age all legible in the bone. It is one of the few places where a hiker's find becomes a data point in a study older than most hikers.
Tally, in the marginA library where every book is a moose — I have never wanted a library card more.
Getting there
Ferries run from Houghton and Copper Harbor in Michigan and from Grand Portage in Minnesota; a seaplane service operates from Houghton. Crossings take from ninety minutes to several hours depending on the route, and Lake Superior can cancel any of them, so build slack into plans. The park is open roughly mid-April to the end of October, with full services from June; it closes entirely for winter.
There are no roads and no vehicles — travel on the island is on foot or by boat. Rock Harbor and Windigo are the two service hubs, with a lodge, campgrounds and ranger stations. Book ferries and lodging well ahead for July and August, carry everything you need, and treat the lake with respect: its water is cold enough to be dangerous in every month of the year.
Common questions
What is the Isle Royale wolf-moose study?
The Isle Royale wolf-moose project is the longest continuous study of a predator-prey system in the world, running annually since 1958. Begun by Durward Allen of Purdue University and now led from Michigan Technological University, it counts the island's wolves and moose every year, mostly from the air in winter.
How do wolves and moose get to Isle Royale?
Neither species is native to the island in deep time. Moose are believed to have arrived around 1900, apparently by swimming from the mainland. Wolves crossed an ice bridge from Canada in the late 1940s. Warming winters have since made ice bridges rare, which is why the National Park Service translocated wolves to the island in 2018 and 2019.
Why did Isle Royale's wolves almost die out?
A canine virus introduced in the early 1980s crashed the wolf population, and the decline of winter ice bridges cut off the arrival of new wolves and new genes from the mainland. By 2018 only two closely related wolves remained. Translocations in 2018 and 2019 restarted the population, and 2026 counts put wolves near a fifty-year high.
How do you get to Isle Royale?
Isle Royale is reachable only by ferry or seaplane. Ferries run from Houghton and Copper Harbor, Michigan, and Grand Portage, Minnesota; seaplanes fly from Houghton. There are no roads on the island, and travel is on foot or by boat from the two hubs at Rock Harbor and Windigo.
Is Isle Royale open in winter?
No. Isle Royale closes entirely from November to mid-April, the rare US national park to shut for the season, because winter conditions on Lake Superior make regular access unsafe. The main exception is the annual winter wolf and moose count, conducted from a small aircraft.
Why is Isle Royale one of the least visited national parks?
Isle Royale requires a ferry or seaplane to reach, has no roads, closes for half the year, and demands self-sufficient travel once there. The result is annual visitation that busier parks exceed in a single day - and visitors who typically stay several days rather than hours.