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
North American P-51 Mustang variants for the P-51 came from tests carried out at facilities such as the USAAF's "Flight Test Engineering Branch", based at Wright Field near Dayton, Ohio and, for the RAF, the Aeroplane & Armament Experimental Establishment (A&AEE), based at Boscombe Down. North American Aviation carried out their own performance tests, as did the only other manufacturer of the P-51, the Commonwealth Aircraft Corporation (CAC) of Australia. North American P-51 Mustang variants Over twenty variants of the North American P-51 Mustang fighter were produced from 1940, when it first flew, to after the Second World War, some of which were employed also