Deadwood Reservoir is a reservoir in the western United States, in Valley County, Idaho. Located in the mountains of the Boise National Forest about 25 miles (40 km) southeast of Cascade, the 3,000-acre (12 km2) body on the Deadwood River is created by Deadwood Dam. The river flows south from the dam and is a tributary of the South Fork of the Payette River. The reservoir and vicinity is commonly used for camping, water skiing, fishing, canoeing, and other outdoor recreation. The full pool surface elevation is just above a mile-high at 5,334 ft (1,626 m) above sea level.