Ontonagon Harbor, Michigan is located about 140 miles east of Duluth, Minnesota, on the south shore of Lake Superior, at mouth of the Ontonagon River. The project was authorized by Rivers and Harbors Acts of March 2, 1867; June 23, 1874; June 13, 1902; June 25, 1910; August 26, 1937; and, October 23, 1962; and by Water Resources Development Acts of November 17, 1986; and, January 3, 1996. The existing project provides for a flared lake approach channel about 850 feet long to deep water and 16 feet deep with depths narrowing from 400 feet at the outer end to 150 feet opposite the outer end of the west pier; a channel between the piers 150 feet wide, 17 feet deep in the outer 250 feet, and 15 feet deep in the inner 2,200 feet; an inner basin 12 feet deep and 900 feet long, extending between lines 50 feet from the existing wharves on each side of the river, the maximum width being 285 feet; and the maintenance of this channel, the basin; and east and west entrance piers and revetments which are 2,315 feet and 2,563 feet long, respectively. The project serves coal wharves and an oil receiving facility. The harbor provides the only refuge for small craft between the Keweenaw Waterway upper entrance and Black River Harbor.