Angostura Reservoir is a reservoir on the Cheyenne River in Fall River County, South Dakota, USA. It was created after the construction of Angostura Dam in 1949 for irrigation. "Angostura" means "narrows" in Spanish.
The reservoir covers an area of 4,407 acres (17.83 km2), has a surface elevation of 3,127 ft (953 m), and a maximum depth of 75 ft (23 m).
The reservoir is the location of the Angostura Recreation Area and is a popular location for boating, swimming, and fishing. The lake supports populations of walleye, northern pike, smallmouth bass, and sunfish. As one of the only large bodies of water in the area, Angostura Reservoir is also an important location for migratory birds.