High Island sits in Lake Michigan, roughly four miles west of the much larger Beaver Island and less than two miles from Trout Island. It belongs to the Beaver Island archipelago, and the state of Michigan owns it, managing it through the Department of Natural Resources as part of the Beaver Islands State Wildlife Research Area. The island takes its name from its most dramatic feature: a massive perched sand dune on the western shore, sculpted by Lake Michigan's prevailing westerly winds into a formation that rises 780 feet above sea level, or 199 feet above the lake's surface. It is a raw, vertical landscape, a wall of sand standing where forest meets open water. The island is uninhabited today. Two abandoned DNR cabins, named Alpha and Omega, sit in disrepair near the last unobstructed trailhead, their roofs leaking, their windows broken, relics of research teams that once worked here.

In 1912, a millenarian religious sect called the House of David, based in Benton Harbor, Michigan, established a timber-cutting and truck farming operation on High Island. The commune's members had taken vows of celibacy and practiced vegetarianism, and they turned the island's soil into productive potato fields, growing root crops in quantities that fed the congregation back on the mainland. At its peak, 120 to 150 House of David members lived in a small village near High Island Bay on the island's eastern shore. The community fascinated and unsettled their neighbors in equal measure, the celibacy vows a source of particular curiosity. The commune's island chapter ended abruptly in 1927 when a sexual scandal involving sect leader Benjamin Purnell shattered the organization's credibility and its members largely abandoned High Island.

Before, during, and after the House of David era, High Island was home to several extended families of Odawa (Ottawa) Native Americans who made their living fishing the waters of the Beaver Island archipelago. The island supported a public school as late as 1936, evidence of a community substantial enough to educate its children. But the fisheries that sustained the Odawa began declining sharply in the 1930s, and the Armistice Day Blizzard of 1940, one of the most devastating storms in Great Lakes history, delivered the final blow. The remaining Odawa families left High Island and relocated to Beaver Island. Their departure marked the end of permanent habitation on an island that had supported human life for generations.

High Island's Great Sand Bay, on the western side where the great dune rises, is one of the last suitable Great Lakes nesting sites for the piping plover, a small shorebird listed as endangered in Michigan. The plovers nest on the open sand, their pale plumage blending with the beach so completely that the eggs are nearly invisible to the untrained eye. Terns also breed on a sandspit at the island's northeast corner. The absence of human residents, the remoteness of the island, and the wildness of its shoreline make High Island an accidental refuge, a place where wildlife thrives precisely because people left. The DNR's management of the island as a wildlife research area ensures that this unintentional sanctuary endures.

The legend of Strang's treasure is High Island's most colorful thread. James Jesse Strang declared himself king of Beaver Island in 1850 and ruled a community of followers for six years until he was shot by disgruntled members of his own flock in June 1856. As the mortally wounded king was transported to Wisconsin for medical care, one of his followers is said to have carried the royal treasury to High Island and buried it thirty paces from a prominent tree overlooking the northeast harbor. Strang died of his wounds, and the secret of the treasure's exact location may have died with his loyal courier. Logging operations that swept across High Island shortly afterward stripped the landscape of its old-growth trees, destroying the one landmark that might have guided a recovery. As of 1987, no treasure had been found, and the island keeps its secret beneath layers of sand and second-growth forest.