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
Toston Dam Toston Dam Toston Dam is a hydroelectric gravity dam located on the Missouri River in Broadwater County, Montana. The dam is long and high, and generates 10 megawatts of power. The dam is a "run-of-the-river" dam because it can generate electricity without needing to store additional water supplies behind the dam. The dam is named after the town of Toston, Montana, which is just away. A $1.12 million dam was originally proposed in 1935. This project never was built. A smaller dam, whose construction would cost $900,000, was proposed in 1938, and the Montana State Water Conservation Board sought Public