What Is Inside Area 51: The Short Answer
The plain answer is an airbase. The CIA publicly acknowledged the site on 25 June 2013, in response to a Freedom of Information Act request filed in 2005, and its declassified history describes runways, hangars, a control tower, workshops, storage and administration buildings, a fire station, a commissary, housing and recreation facilities. It also describes a tank farm built for an unusual jet fuel and a fleet of support aircraft.
The harder answer is that nobody outside the program can say what is inside Area 51 right now. All research and activity there is classified as Top Secret/Sensitive Compartmented Information (TS/SCI), a level reserved for the most tightly controlled programs. The Air Force describes the area as an open training range, and the facility is widely thought to support the development and testing of experimental aircraft and weapons. Beyond that, the official record goes quiet.
That gap between a well-documented past and a sealed present is exactly where the legends grow. For a broader primer on the base itself, see our overview of what Area 51 in Nevada is.
Where Is Area 51, and Why Groom Lake?
Knowing what is inside Area 51 starts with the land itself. The base sits within the Nevada Test and Training Range in southern Nevada, about 83 miles north-northwest of Las Vegas. Officially it is called Homey Airport, carrying the airport codes KXTA and XTA, or simply Groom Lake, after the salt flat beside its airfield. It operates as a remote detachment administered from Edwards Air Force Base in California, under Air Force Materiel Command. Its unofficial names include “Paradise Ranch,” “the Ranch” and “Dreamland,” the last being the call sign for approach control in the surrounding airspace.
The lakebed
Groom Lake is a salt flat roughly three and three-quarter miles from north to south and about three miles across at its widest, sitting around 4,400 feet above sea level. It lies about 25 miles south of Rachel. When Kelly Johnson, the designer of Lockheed’s U-2, flew over it with an inspection team in 1955, he recalled knowing within seconds that it was the place: a natural landing field, “smooth as a billiard table,” that needed no preparation. That flatness, plus the surrounding mountains and the nuclear test site perimeter keeping visitors away, is why it was chosen.
The neighbors
The base shares a border with Yucca Flat, where 739 of the 928 nuclear tests at the Nevada Test Site took place. The Yucca Mountain nuclear waste repository lies to the southwest. Paved roads connect Area 51 to the wider test site network, while Groom Lake Road runs northeast through the Jumbled Hills toward State Route 375, the road known as the “Extraterrestrial Highway.”
The restricted airspace
The original rectangular base measured roughly 6 by 10 miles. Around it sits the “Groom box,” a block of restricted airspace about 23 by 25 miles, officially Restricted Area 4808 North (R-4808N). In January 1962, the Federal Aviation Administration expanded that restricted zone, making the lakebed the center of a 600-square-mile addition.
Why the name?
Nobody is sure. One explanation ties “Area 51” to an Atomic Energy Commission numbering grid, but the base does not actually fit that grid and sits next to Area 15. Another holds that 51 was chosen because the commission was unlikely ever to use it. The name does turn up in a CIA document from the Vietnam War era, and the agency itself tends to use Homey Airport and Groom Lake.
How the Base Was Built: The U-2 and OXCART Years
Most of the detail about what is inside Area 51 traces back to two Cold War programs. Long before spy planes, though, the Groom basin was mining country. Lead and silver were found in the Groom Range in 1864, and an English company, Groome Lead Mines Limited, financed mines there in the 1870s, which is where the name comes from. Mining came and went until the early 1950s. An airfield with two unpaved runways opened on the site in 1942 as an auxiliary field.
Project AQUATONE and the U-2
In April 1955 the CIA set up the Groom Lake test facility for Project AQUATONE, the development of the Lockheed U-2 high-altitude reconnaissance aircraft. Project director Richard M. Bissell Jr. decided the testing was too secret for Edwards Air Force Base or Lockheed’s Palmdale plant. The CIA asked the Atomic Energy Commission to acquire the land, marked “Area 51” on the map, and fold it into the Nevada Test Site.
The first camp was bare. A survey team arrived on 4 May 1955 and laid out a 5,000-foot runway on the southwest corner of the lakebed. A little over three months later there was one paved runway, three hangars, a control tower, basic housing, a mess hall, wells, fuel tanks, a movie theater and a volleyball court. Johnson named it “Paradise Ranch” to coax workers into moving to the middle of nowhere. The first U-2 arrived on 24 July 1955, flown in from Burbank inside a C-124 Globemaster II cargo plane. Staff flew in on Monday mornings and returned to California on Friday evenings.
OXCART and the A-12
The base truly grew with Project OXCART, set up in August 1959 for anti-radar studies and the Lockheed A-12, a high-speed reconnaissance jet similar to the later SR-71 Blackbird. Groom Lake at the time had buildings for only about 150 people, so a construction program called “Project 51” began on 1 October 1960, with crews working double shifts.
The first A-12 was trucked in secretly from Burbank in February 1962 and flew on 26 April 1962, by which point more than 1,000 people worked at the base. By the end of 1963, nine A-12s were stationed there with a CIA unit called the 1129th Special Activities Squadron. On 22 December 1964 the base also hosted the first test flight of the Lockheed D-21, a high-speed reconnaissance drone launched from the back of a two-seat A-12 variant. That program had a fatal cost: in July 1966 a D-21 collided with its launch aircraft, and one of the two crew members drowned after ejecting over the ocean.
Hangars, Runways and Fuel: The Documented Layout
For anyone asking what is inside Area 51 according to records the government has released, the 1960s buildout gives the clearest picture. Here is what that history describes.
- Runways. A 10,000-foot paved runway was built diagonally across the southwest corner of the lakebed. Today the main asphalt runway (14L/32R) is listed at nearly 12,000 feet, alongside a shorter paved strip and four marked runways on the dry lake surface itself, each around 10,000 to 11,400 feet long.
- “The Hook.” Crews marked an Archimedean spiral about two miles across onto the lakebed so an A-12 pilot running out of runway could abort onto the lake rather than plunge into the sagebrush.
- Hangars. Three surplus Navy hangars went up on the north side, along with a newly built Hangar 7. The original U-2 hangars became maintenance and machine shops.
- Fuel. By early 1962 a tank farm of seven tanks held about 1.32 million gallons of JP-7, the special fuel the A-12 needed.
- Daily life. Workshops, storage and administration buildings, a commissary, a control tower, a fire station and housing, including more than 130 surplus Navy duplex units.
- Recreation. A gym, a movie theater, a baseball diamond and a tree-lined reservoir pond about a mile north of the base.
- Support fleet. F-101 Voodoo trainers, T-33 trainers, a C-130 cargo plane, a helicopter for search and rescue, light utility planes, and an F-104 Starfighter used as a chase plane.
It is a surprisingly ordinary list: a fire station, a mess hall, a ball field. The documented answer to what is inside Area 51 turns out to be mostly mundane. The secret was never the buildings. It was the aircraft parked inside them.
What Is Inside Area 51 Today?
The facility built in 1955 has never closed. It is listed as operational, garrisoned by Detachment 3 of the Air Force Test Center. Satellite imagery, including European Space Agency Sentinel-2 images from 2022, shows a developed complex with Groom Lake just to its north-northeast, a long way from the trailer camp of the U-2 days.
Exactly what is inside Area 51 now, in terms of specific aircraft or weapons, is not public. The most grounded reading is that the base continues doing what its history shows it was built for: testing aircraft and systems the military wants kept out of sight. Structures visible from a distance or in imagery invite speculation, including pads, large hangars and outbuildings, but nothing in the public record ties any of them to a specific program.
That is the honest boundary. The past, through the 1960s, is richly documented. The present is a locked door.
The Alien Question: What Believers Claim
For many people, the real question about what is inside Area 51 has nothing to do with jet fuel. The intense secrecy around the base has made it a central part of UFO folklore, the place where, the stories say, the government keeps crashed flying saucers and their occupants.
What the stories say
According to the most popular versions, the hangars hold recovered alien craft that engineers are trying to copy, and somewhere in the complex, often said to be underground, are preserved alien bodies or even living visitors. These tales often link the base to the 1947 Roswell incident in New Mexico, claiming the debris from that crash ended up in Nevada. Over the years, people who said they had worked at or near the base added accounts of reverse-engineering programs, though none of these claims has been backed by documents. Our piece on the alien from Area 51 legend traces how those stories took shape.
The strongest ordinary explanation
The declassified history itself suggests why strange objects were reported over the Nevada desert. The U-2 was built to fly far higher than ordinary aircraft of the 1950s, and the A-12 was faster and shaped unlike anything most pilots had seen. The record notes that pilots flying near the closed airspace spotted the A-12 some 20 to 30 times. A glint at an impossible altitude, or a dark shape moving faster than any known plane, is exactly the kind of thing that turns into a UFO report, and the people who knew what was actually flying were forbidden to say.
Skeptics also point out that extreme secrecy works like a vacuum. When a government will not admit a base exists, which it did not until 2013, any explanation, however wild, faces no official rebuttal.
The case for something stranger
Believers answer that a government willing to keep an entire base officially unacknowledged for nearly sixty years is clearly capable of hiding more, and that “spy planes” may be a convenient cover for programs that remain classified. That argument cannot be disproved, because what is inside Area 51 today remains classified. It also cannot be confirmed. It rests on the absence of information rather than on evidence. For the wider debate over unexplained aerial objects, see our UFO and UAP section, where UAP is short for unidentified anomalous phenomena.
Documented versus claimed
Set side by side, the documented and claimed versions of what is inside Area 51 look like two different places.
| Topic | What the record shows | What is claimed |
|---|---|---|
| Purpose | Built in 1955 for U-2 testing; expanded for the A-12 and D-21 | Storage and study of alien technology |
| Hangars | Navy surplus hangars, Hangar 7, converted U-2 hangars | Recovered flying saucers |
| Underground | No underground complex described in the declassified history | Deep tunnels and secret labs |
| Strange sightings | Spy planes seen by other pilots dozens of times | Alien craft on test flights |
| Current activity | Operational, classified TS/SCI | Ongoing alien research |
Can You See Area 51, and What People Get Wrong
The base is not open to the public, and its boundary and checkpoint are there to keep people out. Visitors who want a sense of the place stick to the public side: the small town of Rachel and the Extraterrestrial Highway, which have become tourist stops in their own right. The base has been viewed and photographed from distant Tikaboo Peak, miles away. The terrain is remote and harsh, and nothing here should be read as encouragement to approach the perimeter. The 2019 “Storm Area 51” event is a reminder of how much attention the place still draws.
The airspace is just as closed. The Groom box is restricted military airspace, and civilian pilots are not allowed into it without authorization.
Common mistakes
- Assuming nothing is known. A great deal about what is inside Area 51, as it was built in the 1950s and 1960s, is described in the CIA’s declassified account.
- Assuming everything is known. The opposite error. The documents stop well short of the present day.
- Treating secrecy as evidence. A classified program proves only that something is classified, not what it is.
- Mixing up the names. Area 51, Groom Lake, Homey Airport, Dreamland and Paradise Ranch all refer to the same place, which leads to stories that seem to describe several bases.
- Taking satellite shapes at face value. A pad or a large roof in imagery says nothing on its own about what sits beneath it.
So what is inside Area 51? Runways cut across a salt flat, hangars built for the most secret aircraft of their age, a fuel farm, a fire station, and a ball field for people who spent their weeks in the desert. Anything newer remains one of the best-kept secrets in the United States, and until more of the base’s work is declassified, the space between the record and the legend stays open. Readers who want to keep following the thread can explore our conspiracy theories, examined section, or settle into the long-form conversations about the unexplained collected in the Troubled Minds Vault.
Questions and answers
What does Area 51 actually have in it?
Declassified CIA history describes runways, hangars, a control tower, workshops, storage and administration buildings, a fire station, a commissary, housing and recreation facilities such as a gym and movie theater. A large tank farm stored special JP-7 fuel for the A-12 spy plane. What the hangars hold today is classified, though the base is widely thought to support testing of experimental aircraft and weapons.
Is Groom Lake still active?
Yes. The facility at Groom Lake has been in use since 1955 and remains operational. It is officially known as Homey Airport, or Groom Lake, and operates as a remote detachment administered from Edwards Air Force Base under Air Force Materiel Command. Its current activities are classified at the Top Secret level, so the details of what is tested there are not public.
What happens if you fly over Area 51?
The airspace around the base is restricted, designated R-4808N and nicknamed the Groom box, and civilian pilots are not permitted to enter it without authorization. Restricted military airspace is enforced, and unauthorized entry can bring serious legal and safety consequences. The approach control for the surrounding area uses the call sign Dreamland. Anyone flying in southern Nevada should treat the restriction as absolute.
Why is it called Area 51?
The origin of the name is not clear. One explanation links it to a numbering grid used by the Atomic Energy Commission at the Nevada Test Site, although Area 51 does not actually fit that system and sits beside Area 15. Another suggests the number was picked because the commission was unlikely ever to use it. The name appears in a CIA document from the Vietnam War era.
Are there aliens in Area 51?
No public evidence shows aliens or alien craft at Area 51. The idea grew from decades of official secrecy, strange objects reported over the Nevada desert, and claims by people who said they had inside knowledge. The declassified history points to high-flying spy planes like the U-2 and A-12, which other pilots had no way to identify at the time.
Stay curious. Keep the question open.
Follow the evidence wherever it leads.
