This 45-mile-long, nine-mile-wide wilderness is tough to reach: plopped in the northwest corner of rugged Lake Superior, it’s a ninety-minute ferry ride from the nearest harbor. That isolation accounts for the island’s most famous residents: a pack of gray wolves whose adventurous ancestors crossed the ice here in 1948 in pursuit of moose. Unfortunately, the pack has dwindled to just 16 members, a result of inbreeding; there are currently only two females, meaning time could be running out for the canines. Take five days to traverse the 40-mile Greenstone Ridge Trail, which spans the island’s entire windswept spine, keep quiet, and if you’re lucky you’ll catch a glimpse of the pack. If not, you’re still in the most pristine boreal forest in the lower 48. Ride to Royale from Houghton, Michigan, on the park’s ship, the Ranger III, and pick up a free backcountry camping permit onboard (ferry, $100 round-trip; $4 visitor fee per person per day). Then traverse the footpath from the northeast at Lookout Louise to the southwest at Windigo, winding through maple and birch forests and up 1,394-foot Mount Desor, Isle Royale’s highest point. There are 36 designated campgrounds—spend a night at Chickenbone Lake, a good swimming spot. Tip: go in late August, when swarming mosquitoes and blackflies are on their way out.