Shadehill Dam is a dam (constructed 1951) on the Grand River in Perkins County in northwestern South Dakota in the United States, about 10 miles (16 km) south of Lemmon.

The dam and its impoundment, Shadehill Reservoir, serve mainly for flood and silt control, wildlife conservation and recreation.

Located directly below the confluence of the North and South Forks of the Grand River, the dam is operated by the U.S. Bureau of Reclamation, and is part of the Shadehill Unit of the Pick-Sloan Missouri Basin Program.

[4] At full pool, the reservoir has a capacity of 468,585 acre-feet (0.577991 km3), with a surface area of 12,150 acres (4,920 ha).

[2][5] Shadehill Dam was originally intended to serve irrigation purposes as well, but after determining that the water in the reservoir was too saline the Bureau of Reclamation dropped this phase from the project.