Oahe Dam Oahe Dam The Oahe Dam is a large earthen dam on the Missouri River, just north of Pierre, South Dakota, United States. The dam creates Lake Oahe, the fourth largest man-made reservoir in the United States. The reservoir stretches up the course of the Missouri to Bismarck, North Dakota. The dam's power plant provides electricity for much of the north-central United States. It is named for the Oahe Indian Mission established among the Lakota Sioux in 1874. The project provides flood control, Hydropower generation, irrigation, and navigation benefits. Oahe Dam is one of six Missouri River mainstem dams, the next
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,