Saturday, September 8, 1860 at 2:30 a.m., the sidewheel steamship was full of Milwaukees Union Guard and civilians returning to Milwaukee from political rallies in Chicago. During gale force winds and thunderstorms, the Lady Elgin was struck on the port side by the schooner Augusta. Within 20 minutes, the Lady Elgin broke apart and sank as the Augusta raced to Chicago to save itself. After a perilous night, about 350-400 passengers were drifting upon flotsam in stormy waters. After several hours, and still two miles from shore, most of the survivors lost their fight to live as they succumbed to the waves breaking on the rocky shoreline. Approximately 300 perished. The Lady Elgin disaster resulted in the greatest loss of lives in open water in the history of the Great Lakes.