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 power, providing cheap electricity and allowing the area to modernize to a considerable extent. The city of Norris, located a few miles south of the dam, was developed as a planned city alongside the dam project. The construction of Norris Dam began on October 1, 1933 and its gates were closed on March 4, 1936. The east section of Norris Dam State Park was developed in the 1930s by the Civilian Conservation Corps as a "demonstration recreational project" of the Tennessee Valley Authority. The CCC built a lodge, several rustic cabins, and an amphitheater. The land was sold to the