Area 51 the base extends further east. After leaving the restricted area, Groom Lake Road descends eastward to the floor of the Tikaboo Valley, passing the dirt-road entrances to several small ranches, before converging with State Route 375, the "Extraterrestrial Highway", south of Rachel. Area 51 shares a border with the Yucca Flat region of the Nevada Test Site, the location of 739 of the 928 nuclear tests conducted by the United States Department of Energy at NTS. The Yucca Mountain nuclear waste repository is southwest of Groom Lake. Groom Lake is a salt flat in Nevada used for runways of the
Maryland Route 51 state highway reduces to a two-lane road after passing Uhl Highway, an old alignment of MD 51 that is unsigned MD 51E. The rail yard ends at Mexico Farms Road, which provides access to Mexico Farms Airport and the Warrior Run Generating Station. Within the hamlet of North Branch, MD 51 intersects as other end of Uhl Highway as well as Pittsburgh Plate Glass Road, which serves the North Branch Industrial Complex, including Federal Correctional Institution, Cumberland. MD 51 enters a rural area and parallels the C&O Canal southeast through Spring Gap. The state highway turns away from the Potomac