Lake Oahe Pierre, South Dakota and extends nearly as far north as Bismarck, North Dakota. Mobridge, South Dakota is located on the eastern shore of the central portion of the lake. Bridges over Lake Oahe include US Route 212 west of Gettysburg, South Dakota and US Route 12 at Mobridge. The former town of Forest City has been flooded beneath Lake Oahe, about 9 miles west of Gettysburg. Prehistoric archaeological sites have been explored in the area, including Molstad Village near Mobridge. It dates to before the emergence of the Arikara, Hidatsa and Mandan as separate peoples, and has been designated as
Oahe Dam earth main dam reached its full height in October 1959. It was officially dedicated by President John F. Kennedy on August 17, 1962, the year in which it began generating power. The original project cost was $340,000,000. Tours of the powerplant are given daily, Memorial Day through Labor Day. As a result of the dam's construction the Cheyenne River Indian Reservation lost bringing it down to today. Standing Rock Reservation lost leaving it with . Much of the land was taken by eminent domain claims made by the Bureau of Reclamation. Over and above the land loss, most of the