Cottonwood Springs Dam is a dam in Fall River County, South Dakota in the southwestern part of the state, south of the Black Hills.
The earthen dam was constructed in 1969 by the U.S. Army Corps of Engineers with a height of and a length at its crest of . It impounds Cottonwood Springs Creek for area flood control.
The reservoir it creates, Cottonwood Springs Lake, has a water surface of and has a maximum capacity of . Recreation is year-round and includes camping, hiking, and fishing. Recreation is managed by the Corps of Engineers.
The dam and lake is approximately west of Hot Springs, South Dakota. Cold Brook Dam, another Corps of Engineers dam is located about northeast.
The dam and reservoir are located within the Cheyenne River watershed.