4w D5 Reservoir (historical) is a reservoir located in Niobrara County, Wyoming. It appears on the Wagonhound Creek NE USGS 7.5-minute topographic quadrangle. The elevation at this location is approximately 4,202.76 feet (1,281.00 m) above sea level. The nearest populated place is Underwood Crossing, approximately 5.3 miles to the W.