Skull Cave is a small and shallow cave located on the central part of Mackinac Island in Michigan, United States. The cave was formed during the time after glaciers melted, when the waters of Lake Algonquin, an older lake that existed before today's Lake Huron, carved it out.

Skull Cave is mainly important because of its history. People think it was used as a place where Native Americans from the Straits of Mackinac area buried their dead in the 1700s.

While it was used for burials, the cave also served as a hiding place in 1763 for Alexander Henry, a fur trader who survived being captured at Fort Michilimackinac during Pontiac's War. In his "Memoirs," Henry described spending a night in the cave, which was filled with bones.

Skull Cave is inside Mackinac Island State Park. It is found 0.4 miles (0.6 km) north of Fort Mackinac in the island's interior. It was named a Michigan Historic Site on January 12, 1959, and received state historical marker number #L0004.