St. Vital Island is an island in Bay De Noc Township, Delta County, Michigan. The island is located in Big Bay de Noc in Lake Michigan. It is 20.52 acres (8.30 ha) in size and under a half mile from the Stonington Peninsula shore. St. Vital Island is uninhabited and owned by the United States Forest Service. It is part of the Hiawatha National Forest. The island is home to a small colony of nesting Common terns and Black-crowned night herons.