Pactola Dam, Embankment dam in Pennington County, United States.

Pactola Dam is an earth-filled embankment dam on Rapid Creek, about 10 miles west of Rapid City. Its main dam stands 245 feet high, with two auxiliary dikes on the northern side; combined they run 2,236 feet and hold 4,532,000 cubic yards of material. U.S. Route 385 crosses the crest, and the dam impounds Pactola Lake, 1,232 acres at normal level.

Federal authorities built this structure between 1952 and 1956 as a major postwar infrastructure project. The construction required massive amounts of earth and rock material and permanently transformed the region's landscape and water management.

The dam's name comes from a former mining settlement that referenced the gold-rich Pactolus River of ancient Lydia. This historical connection still shapes how people understand the region and its past tied to gold extraction.

The reservoir offers year-round recreation with boating and fishing as popular activities. Spring through autumn provides the best visiting conditions with pleasant weather and most recreational facilities in operation.

U.S. Route 385 runs directly along the crest of the dam, so drivers cross the structure itself. The reservoir is known for its large lake trout, and the stretch of Rapid Creek just below the dam is described as an exceptional fly fishing location.