Thunder Bay Island

Thunder Bay Island is a 215-acre (87 ha) island in Lake Huron. The island is one of eight constituent islands of the Michigan Islands National Wildlife Refuge. The island is part of Alpena Township in Alpena County. It marks the entrance to Thunder Bay, the harbor of Alpena, Michigan and the location of the Thunder Bay National Marine Sanctuary.

The island is the home of a historic Thunder Bay Island Light, which in its current form dates to 1857,^[1] and adjacent quarters for the lightkeeper. The island also contains the sites of quarters for lifesaving service personnel and private-sector fishermen.