Area 51 is a military base, and a remote detachment of Edwards Air Force Base. The intense secrecy surrounding the base, whose very existence the U.S. government did not even acknowledge until July 14, 2003 , has made it the frequent subject of conspiracy theories and a central component to unidentified flying object (UFO) stories.

It is located in the southern portion of Nevada in the western United States, 83 miles (133 km) north-northwest of Las Vegas. Situated at its center, on the southern shore of Groom Lake, is a large military airfield. The base's primary purpose is undetermined, however it appears to support development and testing of experimental aircraft and weapons systems.

Though the name Area 51 is used in official Central Intelligence Agency (CIA) documentation, other names used for the facility include Dreamland, Paradise Ranch, Home Base, Watertown Strip, Groom Lake, and most recently Homey Airport. The area is part of the Nellis Military Operations Area, and the restricted airspace around the field is referred to as (R-4808N), known by the military pilots in the area as "The Box" or "the Container."

The facility is not a conventional airbase, as frontline operational units are not normally deployed there. It instead appears to be used for highly classified military/defense Special Access Programs (SAP), which are unacknowledged publicly by the government, military personnel, and defense contractors.

(Adapted from the Wikipedia entry on Area 51)