Angostura Reservoir, body of water

Angostura Reservoir is a reservoir on the Cheyenne River in Fall River County, South Dakota, formed when Angostura Dam was completed in 1949 by the U.S. Bureau of Reclamation for irrigation. It covers 4,407 acres (17.83 km2) at a surface elevation of 3,127 ft (953 m), with a maximum depth of 75 ft (23 m).

Angostura Reservoir was built in 1949 as part of the Pick-Sloan Missouri Basin Program to manage water resources and support irrigation in the region. The dam, constructed by the Bureau of Reclamation, controls the Cheyenne River's flow for agricultural and water supply needs.

The name Angostura is Spanish for 'narrows'. The reservoir lies in Fall River County, and the Angostura Recreation Area around it is used for boating, swimming, camping and fishing. The lake holds walleye, northern pike, smallmouth bass and sunfish.

The reservoir is located about 10 miles southeast of Hot Springs, South Dakota, off U.S. Highway 385-18 and is open year-round with an entrance fee required. Well-marked roads, several campgrounds with more than 170 campsites, boat ramps, and accessible facilities including a visitor center make planning and navigation straightforward.

The reservoir's name comes from the Spanish word for "narrows", a reference to the constricted stretch of the Cheyenne River at Jackson Narrows, one of the features around the lake. The surrounding terrain is mostly shrub-steppe, and the water measures roughly 7.6 km north to south and 10 km east to west.