Deerfield Reservoir is located 20 miles west of Hill City, SD. The Bureau of Reclamation manages the dam and water. Castle Creek flows into and out of the reservoir and provides additional fishing opportunities. Ice fishing, snowmobiling and ice skating are popular winter sports here. The complex has three campgrounds, two boat launches, two picnic areas and the Deerfield Lake Loop Trail (Trail #40L). Travel on the reservoir is limited to five miles per hour and there is a no-wake restriction which provides for peaceful fishing and boating experiences.