The Straits of Mackinac (/ˈmækɨnɔː/ MAK-in-aw) is the narrow waterway separating the U.S. state of Michigan's Lower Peninsula from its Upper Peninsula. The Straits of Mackinac connect two of the Great Lakes, Lake Michigan and Lake Huron. The straits are five miles (8.0 km) wide and 20 fathoms (120 ft; 37 m) deep.