Area 51 Nellis Bombing Range Test Site airport (KXTA) on the north of the Area 51 USAF military installation. The lake at elevation is approximately from north to south and from east to west at its widest point. Located within the namesake Groom Lake Valley portion of the Tonopah Basin, the lake is south of Rachel, Nevada. The origin of the Area 51 name is unclear. The most accepted comes from a grid numbering system of the area by the Atomic Energy Commission (AEC); while Area 51 is not part of this system, it is adjacent to Area 15. Another explanation is
Area 51 around the field is referred to as Restricted Area 4808 North (R-4808N). The base's current primary purpose is publicly unknown; however, based on historical evidence, it most likely supports the development and testing of experimental aircraft and weapons systems (black projects). The intense secrecy surrounding the base has made it the frequent subject of conspiracy theories and a central component to unidentified flying object (UFO) folklore. Although the base has never been declared a secret base, all research and occurrences in Area 51 are Top Secret/Sensitive Compartmented Information (TS/SCI). On 25 June 2013, following a Freedom of Information Act (FOIA)