Fort Mackinac (/ˈmækɪnɔː/ MAK-in-aw) is a former British and American military outpost garrisoned from the late 18th century to the late 19th century in the city of Mackinac Island, Michigan, on Mackinac Island. The British built the fort during the American Revolutionary War to control the strategic Straits of Mackinac between Lake Michigan and Lake Huron, and by extension the fur trade on the Great Lakes. The British did not relinquish the fort until thirteen years after the end of the American Revolutionary War.Fort Mackinac later became the scene of two strategic battles for control of the Great Lakes during the War of 1812. During most of the 19th century, it served as an outpost of the United States Army. Closed in 1895, the fort has been adapted as a museum on the grounds of Mackina