Fort: Fort George, Mackinac Island, MI (1814)

Built (1814) → Fort George → Became Fort Holmes in xxxx → Dismantled in xxxx.

Built by: British, U.S. in 1815 and renamed Fort Holmes.

Military Use: Defend the Straits of Mackinac

This was always  an outpost of nearby Fort Mackinac on Mackinac Island. 

In 2015 the Mackinac Island State Park completed a reconstruction of Fort Holmes that resumes the appearance that the redoubt had in 1817 The blockhouse includes interpretive panels inside, and is open in the summer. Many visitors come to the fort site for a view of the Straits. which is visible from this lookout point approximately 310 feet (94 m) above the surface of Lake Huron. [Wiki]