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
Area 51 delivered by Lockheed to Area 51, later the A-7D's were used for F-117A chase testing and other weapon tests at the Nellis Range. 15 October 1982 is important to the program because on that date Major Alton C. Whitley, Jr. became the first USAF 4450th TG pilot to fly the F-117A. Although ideal for testing, Area 51 was not a suitable location for an operational group, so a new covert base had to be established for F-117 operations. Tonopah Test Range Airport was selected for operations of the first USAF F-117 unit, the 4450th Tactical Group (TG). From October 1979,