Angostura Dam, Embankment dam in Fall River County, United States

Angostura Dam is a 193-foot-high, 2,030-foot-long embankment dam across the Cheyenne River in Fall River County, South Dakota, about 75 miles south of Rapid City. Its left side is a concrete gravity section reaching from the left bank to mid-river, joined by an earth-fill embankment to the right bank. The dam impounds the Angostura Reservoir, which has 36 miles of shoreline.

The dam was conceived as early as 1913, but only gained broad support after 1930s drought caused crop failures. Construction began on 23 August 1946 and was completed on 7 December 1949 as part of the Pick-Sloan Missouri Basin Program. The U.S. Bureau of Reclamation owns and operates it.

The name refers to a narrow river passage, a term with Spanish origins reflecting the local geography. People gather here for outdoor activities and fishing, making it an important recreational destination for the region.

The dam stands about 14.5 km southeast of Hot Springs, roughly 121 km south of Rapid City, reached by road through Fall River County. The Angostura Recreation Area around the reservoir provides the main access to the shoreline and the water. The crest is 619 m long and 3 m wide, with 295 m of concrete gravity dam on the left bank and an earth-fill section on the right.

The reservoir behind it extends far along the riverbed and hosts several fish species that attract anglers throughout the year. The extended shoreline creates multiple access points for boating and water sports.