The origin of the name "Area 51" is unclear. It is believed to be from an Atomic Energy Commission (AEC) numbering grid, although Area 51 is not part of this system; it is next to Area 15. Another explanation is that 51 was used because it was unlikely that the AEC would use the number.[18] According to the Central Intelligence Agency (CIA), the facility is called Homey Airport (XTA/KXTA) and Groom Lake,[19][20] though the name "Area 51" was used in a CIA document from the Vietnam War.[21] Nicknames for the facility include "Paradise Ranch" and "Dreamland";[22] the latter is the approach control call sign for the surrounding area.[23][24] Air Force public relations has referred to the facility as "an operating location near Groom Dry Lake". The special use airspace around the field is referred to as Restricted Area 4808 North (R-4808N).
Lead and silver were discovered in the southern part of the Groom Range in 1864,[26] and the English company Groome Lead Mines Limited financed the Conception Mines in the 1870s, giving the district its name (nearby mines included Maria, Willow, and White Lake). J. B. Osborne and partners acquired controlling interest in Groom in 1876, and Osborne's son acquired it in the 1890s.[27] Mining continued until 1918, then resumed after World War II and continued until the early 1950s.
The airfield on the Groom Lake site opened in 1942 as Indian Springs Air Force Auxiliary Field[28] with two unpaved 5,000-foot (1,524 m) runways.