Jennings Randolph Lake and Dam is located on the North Branch of the Potomac River, five miles north of Elk Garden, Mineral County. Originally named Bloomington Lake for nearby Bloomington, Maryland, the project was renamed in honor of U.S. Sen. Jennings Randolph. Completed in 1981 at a cost of $175 million, the dam is 296 feet high with a top length of 2,130 feet. It is one of the largest rock-filled, rolled-earth dams east of the Mississippi. Its reservoir has a capacity of 31 billion gallons.

Built to improve the water quality, the lake acts as a pollution trap. It has a control tower with five pairs of intakes located at different depths. Since the acid drainage from abandoned coal mines in the reservoir's watershed stratifies at different levels, regulating the outflow through the several intakes controls the acid content of the water released from the lake. This has resulted in improved water quality downstream, with the return of aquatic life and the establishment of a successful trout fishery at the base of the dam. The dam also helps to control flooding along the North Branch. Releases of water for whitewater rafters, kayakers, and canoeists are made from the reservoir on selected spring weekends. There are boat launches, scenic overlooks, a campground, and a picnic area at the lake. The lake is a handsome body of water and since its establishment has attracted nesting bald eagles and ospreys.