I have a habit of daydreaming over maps.

When I open my Rand McNally to pages 54 and 55, I see not just the enigmatic shape of Minnesota, but all of the places I've been and all of the places I've yet to explore.

My eyes have been drawn many times to the upper right-hand corner of the page, where a sliver of land in Lake Superior edges into view. A dotted line crosses the blue ink of the lake, connecting the land to the town of Grand Portage: the ferry route to Isle Royale National Park.

What I hold in my hands is paper and ink; but in my mind, I see a boat, I see the oceanic expanse of Superior, I feel the boat rocking and spray coming over the bow. I see a low green landmass on the horizon: an island wilderness without cars or roads, without towns or telephone wires -- a place where moose and wolves are the most populous mammals for most of the year. ¶ I have been on that boat in my mind many times.

Last August, I put down the atlas and went to Isle Royale.

A friend told me that the ferry to Isle Royale usually runs a little late. Not on the day I left. I got to the dock at 7:55 a.m., and I was the 48th passenger on the boat, which was loaded to capacity. We left at 7:56.

The M.V. Voyageur II is a utilitarian craft, 60 feet long, with an open bow and a bus-like superstructure. I watched a deckhand heave my backpack onto the roof, and I stepped into the crowded cabin. I felt the diesel engine vibrate as I nudged my way through Gore-Tex-clad passengers to the open area aft, where I squeezed into the last, narrow opening on a bench.

On open water, a cold north wind whipped spray off the whitecaps, and the boat lurched on swells as it headed east. I had to keep my eyes on the receding horizon to avoid getting seasick. This wasn't quite the way I'd imaged the journey, but I didn't care; in three hours I'd be there.

Isle Royale National Park is made up of more than 400 islands, spread out over 850 square miles. The namesake (and biggest) island is more than 40 miles long and about 9 miles across at its widest.

Although Minnesota and Ontario are both closer, the island is part of Michigan. Why? Michigan lost Toledo in a dispute with Ohio in the 1830s and was compensated with most of the Upper Peninsula and Isle Royale. This was before Minnesota was around to object, and no one asked the Ojibwe.

• • •

Disheveled backpackers, ready to start their journeys home, greeted us on the dock at Windigo, the marina and ranger station at the west end of the island. The Voyageur has a two-day cycle. After it stops at Windigo, it circumnavigates the island, picking people up and dropping them off at various points along the way. At Rock Harbor, on the east end, it overnights before returning to Grand Portage.

As the ferry departed, a ranger gave the fresh group a brief orientation. "Isle Royale is the least-visited park in the system, with 17,000 annual visits," Valerie Bowen said. "But it's the most revisited park; 40 percent are return visitors. Some magic keeps drawing people back."

She warned us to keep our distance from the park's numerous moose and reassured us that the 21 wolves (in three packs) posed no threat.

I registered a backcountry hiking plan, paid the $4 per day user fee, and set off on some of the park's 165 miles of trail for my campsite on Huginnin Cove, a two-hour walk north from Windigo.

Late summer sun flooded the dense woods with light. From the margins of the well-worn trail, asters bloomed, beaming like violet asterisks. The West Huginnin Cove Trail crossed the ridges that run the length of the island. When I reached the top of the last ridge, I could see across the lake to Ontario, where a plume of smoke rose from Thunder Bay's paper mills.

The cove was a three-quarters circle, a hundred yards wide at the mouth, with a scattering of boulders rising out of the water just off shore. Five campsites, tucked into the woods, were arrayed around the cove. I chose No. 1, a clearing furnished with found items and carpeted with pine duff. Half of a cable spool, 6 feet across, had been set up as a table with driftwood benches.

As I pitched my tent, a barrage of screeching made me jump. An Isle Royale red squirrel -- about half the size of the gray ones commonly seen in Twin Cities yards -- was clenching his paws to his chest and shooting machine-gun blasts of chatter from a nearby white pine. It appeared I was intruding on his turf. The performance had all the contorted rage of Robert DeNiro playing Travis Bickle in "Taxi Driver."

Bowen had warned us about this territorial species of rodent that can be seen nowhere else on Earth. They've lived in isolation long enough that they are considered a separate subspecies from the red squirrels on the North Shore, and they are particularly cantankerous.

I set up my tent and made dinner, periodically enduring the curses of Tamiasciurius hudsonicus regalis -- the regal red squirrel, or as I liked to think of him, Travis Bickle Jr.

Just about the time darkness came, so did the rain. I fell asleep to the low rumble of thunder.

• • •

The next day, the sun re-emerged and I hiked back to Windigo for Valerie Bowen's lecture on Isle Royale's moose.

Bowen, a slender woman with an enormous bouquet of curls erupting from under her ranger hat, gave an engaging talk to the dozen campers gathered under the picnic shelter.

"Because Isle Royale is separated from the mainland by at least 14 miles of water or ice, it has only 18 mammal species -- or about half what you'd find along the North Shore," she said. It has one large predator, wolves, and one large prey species, moose. Scientists estimate that moose arrived about 1900, probably by swimming, while wolves arrived only in 1950, by crossing the ice.

While the population of each species has waxed and waned, the moose population has been under increasing pressure; at the peak, about 2,500 moose roamed the island. Last year, the population was counted at 385, the lowest since the study began.

There are many theories about why the moose are in decline, Bowen said. "Warmer winters and springs mean more ticks, which stress moose," she said. "Warmer summers also stress them. Stressed moose are easier prey for wolves."

Bowen told me she'd been coming back to Isle Royale for five years, living on the island from May 1 to Oct. 31. She'd worked at several other national parks, including Acadia in Maine, but she keeps coming back to Isle Royale.

"At Acadia, when it rains, people get in their cars and leave," she said. "You can't do that here."

"For me, there's a magic to it," she said. "I think it has to do with it being an island -- the things you have to leave behind when you cross the water to come here."

• • •

I had another day of hiking and one more blissful night at Huginnin Cove before I began the journey home.

Instead of picking up the ferry as it heads directly back to Grand Portage, I got on it a day early, so I could circumnavigate the island. It was a six-hour ride to Rock Harbor on calm water in a half-empty ferry. Mile after mile, the rocky shore unreeled past the rail. Rock Harbor, with a ranger station, small hotel, bar and restaurant and dozens of people milling about, seemed hopelessly busy after the solitude of Huginnin Cove. Instead of the murmur of Lake Superior, I fell asleep to the sound of other campers playing cards next door.

That was a small price to pay. The last leg of the ferry ride was better than I'd imagined it during those years of map-gazing. The sun was out, the water calm, and I got to ride on the bow of the Voyageur as it navigated between islands and in and out of the coves along the island's ragged southern shore.

Riding with me was Tom Holden, a stout fellow sporting a handlebar mustache and wearing vintage overalls. A resident of Superior, Wis., he said he'd been coming to Isle Royale since 1963. Most years, he's come by himself. He was just beginning his weeklong journey. The ferry would be dropping him off at the campground at Chippewa Harbor, a sheltered inlet with sizable hills rising from calm water.

"I think this is the 44th year," he said. "I stay in the same camp shelter every time. I make a little mark in the rafters to keep track."

I asked him what he was going to do. He grinned broadly. "I'm going to do nothing," he said. "I've been daydreaming about it since last year."

Chris Welsch • 612-673-7113