 Marie, Ontario, is to the northwest across the St. Marys River, but with no direct transportation connection.Sugar Island Township is one of only seven municipalities in the state of Michigan to consist entirely of islands, including Grosse Ile Township, Drummond Township, Bois Blanc Township, Mackinac Island, Peaine Township, and St. James Township.According to the United States Census Bureau, the township has a total area of , of which is land and , or 35.46%, is water.