Northeast arm of Lake Michigan , indenting northwestern Michigan, U.S. Located off the coast of the Lower Peninsula, the head of the bay is 32 mi (52 km) long and 12 mi (19 km) wide.
It is divided into the east and west arms by Old Mission Peninsula, with Traverse City at its base. The Leelanau Peninsula lies west of the bay, which is noted for its year-round fishing. The area is an important summer resort region.