Lake Oahe Lake Oahe Lake Oahe (oh-WAH'-hee) is a large reservoir behind Oahe Dam on the Missouri River; it begins in central South Dakota and continues north into North Dakota in the United States. The lake has an area of and a maximum depth of . By volume, it is the fourth-largest reservoir in the US. Lake Oahe has a length of approximately and has a shoreline of . 51 recreation areas are located along Lake Oahe, and 1.5 million people visit the reservoir every year. The lake is named for the 1874 Oahe Indian Mission. Lake Oahe begins just north of
Norris Dam State Park dam to the base of River Ridge at the Claiborne-Grainger county line. The lake also spans the lower of the Powell River from the river's mouth to a few miles south of Harrogate, and the lower of Cove Creek. The Norris Dam Reservation, which is managed by the Tennessee Valley Authority, consists of the area immediately around Norris Dam and immediately downstream from the dam on both sides of the Clinch. The western half of the reservation, which is largely undeveloped, is known as the River Bluff Small Wild Area. Norris Dam State Park consists of two sections along the