Lightships are floating lighthouses that are anchored in areas where it was too deep, expensive or impractical to construct a lighthouse. Lightships displayed a light at the top of a mast and, in areas of fog, also sounded a fog signal and radio beacon.
The Huron Lightship was commissioned in 1921 and served in various locations on Lakes Michigan and Huron. For 36 of years she was stationed at Corsica Shoals, a sandy area 6 miles north of Port Huron. When decommissioned in 1970 she was the last lightship operating on the Great Lakes. She is now permanently moored on the banks of the St. Clair River in Pine Grove Park in Port Huron, where it is open for tours in the summer months.