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
Hoover Dam Police Security Zone encompasses around Hoover Dam and Lake Mead; before the opening of the bypass, this included of U.S. Highway 93 (US 93). Vehicles had to pass through inspection checkpoints, located on US 93 north of the dam in Nevada, and south of the dam in Arizona, before crossing. With the opening of the bypass, traffic patterns changed dramatically. Through traffic no longer goes through a checkpoint on either side of the river. On the Nevada side, the dam road now branches off US 93 before the checkpoint, which remains in operation to screen dam visitors. On the Arizona side,