Sheridan Lake, reservoir in Pennington County, South Dakota

Sheridan Lake is a reservoir on Spring Creek in Pennington County, South Dakota, within Black Hills National Forest. Sheridan Dam, an earthen structure 134 feet tall and 850 feet long at its crest, was built in 1939. The reservoir holds 22,043 acre-feet at maximum capacity and 13,395 acre-feet at normal storage. Facilities include a marina, swimming beaches, campgrounds and picnic areas on the north and south shores.

Sheridan Lake is a reservoir on Spring Creek in Pennington County, built over the site of Sheridan, the first county seat of Pennington County. Sheridan Dam, an earthen structure 134 feet tall with an 850-foot crest, was completed in 1939. The United States Forest Service owns and operates the lake as a recreation area of the Black Hills National Forest.

Sheridan Lake lies on the site of Sheridan, the first county seat of Pennington County, and the town's name carried over to the water. Visitors today see a marina, a swimming beach and campgrounds on the North Shore, with more campgrounds and a beach on the South Shore. The dam across Spring Creek is small and reached only on foot.

The lake is easy to reach via US Route 385 and offers parking, toilets, and picnic areas at both beaches plus two boat ramps on each side. Campsites operate on a first-come, first-served basis except for some reserved spots, so arrive early especially during peak season.

The lake maintains a steady water level throughout the year because it is not used for flood control or irrigation, making it a reliable spot for fishing and boating. This characteristic sets it apart from many other lakes in the region that experience seasonal water fluctuations.