The Baileys Harbor rangelights were built in 1869 by the U.S. Lighthouse Service. The upper range light, located 950 feet inland, has a white light 17 feet higher than the red light in the lower rangelight. Ships that stayed vertically aligned with the two lights at night or the towers during the day were on range as they approached Baileys Harbor and safely sailed past hidden reefs and shallow waters. The lights were originally fueled by lard, then kerosene and acetylene gas before being electrified in 1930. The rangelights were listed on the National Register of Historic Places in 1989. They are the last remaining set of rangelights of this design on the western Great Lakes that are properly aligned. They are listed by the U.S.C.G. as a navigational aid and are operated by the Ridges Sanctuary.