42°11′00″N 87°39′00″W / 42.18333°N 87.65000°W
PS Lady Elgin was a wooden-hulled sidewheel steamship that sank in Lake Michigan off the fledgling town of Port Clinton, Illinois, whose geography is now divided between Highland Park and Highwood, Illinois, after she was rammed in a gale by the schooner Augusta in the early hours of September 8, 1860. The passenger manifest was lost with the collision, but the sinking of Lady Elgin resulted in the loss of about 300 lives in what was called "one of the greatest marine horrors on record". Four years after the disaster, a new rule required sailing vessels to carry running lights. The Lady Elgin disaster remains the greatest loss of life on open water in the history of the Great Lakes.
