Big Bend Dam is a major rolled-earth embankment dam on the Missouri River, completed in 1963 by the Army Corps of Engineers as part of the Pick-Sloan Missouri Basin Program. It backs up the river to form Lake Sharpe, a reservoir stretching roughly 80 miles upstream. The dam itself sits just west of Fort Thompson, and you can drive across it on a paved road — the views across the water and the surrounding hills are among the better vantage points in the area.
The dam's construction came at considerable cost to the Crow Creek and Lower Brule Sioux tribes, whose reservation land was partially inundated and whose communities were relocated with compensation widely regarded as insufficient. Understanding that context matters when you visit: the scenic reservoir was bought with someone else's homeland. The dam remains an active hydroelectric facility operated by the Army Corps; the visitor overlook on the west side is open during daylight hours.