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
Parker Dam Parker Dam Parker Dam is a concrete arch-gravity dam that crosses the Colorado River downstream of Hoover Dam. Built between 1934 and 1938 by the Bureau of Reclamation, it is high, of which are below the riverbed, making it the deepest dam in the world. The dam's primary functions are to create a reservoir, and to generate hydroelectric power. The reservoir behind the dam is called Lake Havasu and can store or over 210 billion US gallons. The dam straddles the state border at the narrows the river passes through between the Whipple Mountains of California and the Buckskin Mountains