The Oahe Dam is a large earth-fill dam located on the Missouri River in South Dakota. Completed in 1962, it was built primarily for flood control, irrigation, and hydroelectric power generation. The dam creates Lake Oahe, one of the largest man-made reservoirs in the United States, which stretches over 231 miles. The Oahe Dam is operated by the U.S. Army Corps of Engineers and plays a crucial role in managing water resources in the region. It provides recreational opportunities, such as fishing and boating, while also supporting local agriculture through irrigation.