Area 51 is a military base

Military base

A military base is a facility directly owned and operated by or for the military or one of its branches that shelters military equipment and personnel, and facilitates training and operations. In general, a military base provides accommodations for one or more units, but it may also be used as a...

, and a remote detachment of Edwards Air Force Base

Edwards Air Force Base

Edwards Air Force Base is a United States Air Force base located on the border of Kern County, Los Angeles County, and San Bernardino County, California, in the Antelope Valley. It is southwest of the central business district of North Edwards, California and due east of Rosamond.It is named in...

. It is located in the southern portion of Nevada

Nevada

Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...

 in the western United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, 83 miles (133 km) north-northwest of downtown Las Vegas

Las Vegas, Nevada

Las Vegas is the most populous city in the U.S. state of Nevada and is also the county seat of Clark County, Nevada. Las Vegas is an internationally renowned major resort city for gambling, shopping, and fine dining. The city bills itself as The Entertainment Capital of the World, and is famous...

. Situated at its center, on the southern shore of Groom Lake

Groom Lake

Groom Lake is a salt flat in Nevada used for runways of the Nellis Bombing Range Test Site airport on the north of the Area 51 USAF military installation. The lake at elevation is ~ from north to south and from east to west at its widest point...

, is a large military airfield. The base's primary purpose is to support development and testing of experimental aircraft and weapons systems.

The base lies within the United States Air Force

United States Air Force

The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...

's vast Nevada Test and Training Range

Nevada Test and Training Range

The Nevada Test and Training Range is a training facility of the United States Air Force located in the desert of southern Nevada in the United States. It is the largest of its kind in the US, and is operated by the USAF Warfare Center's 98th Range Wing...

 (NTTR), formerly called the Nellis Air Force Range (NAFR).