This light marks one of the four passages between Lake Michigan and the bay of Green Bay. The passage runs on the north side of St. Martin Island. The light is located on the northeast end of the island and marks the western entrance to the passage.

Constructed in 1905, the tower is unique on the Great Lakes. The hexagonal tower is composed of bolt-together cast iron panels supported by six exterior channel posts. The tower is mounted on a concrete base and is 75 feet high overall. The watch room and lantern room are cylindrical. The original Fourth Order lens is on display at the Point Iroquois Lighthouse Museum near Brimley. Michigan. The present light is a modern plastic lens which is 84 feet above the lake level.

The station consists of a large two and ½ story, cream colored brick duplex keeper’s dwelling. A fog signal building and oil storage house also survive. Most of the buildings are suffering from severe neglect.