Iosco (Official number 100484) was a Great Lakes freighter that served on the Great Lakes from her construction in 1891 to her foundering on September 2, 1905, when she and her tow, the schooner barge Olive Jeanette sank on Lake Superior. While Olive Jeanette's wreck was located in over 300 feet (91 m) of water about eight miles (13 km) off the Huron Islands in the 1990s, Iosco's wreck has not yet been found.