Raven Rock Mountain Complex: Site R, the Underground Pentagon

The Raven Rock Mountain Complex, better known as Site R, is the Pentagon’s emergency command centre, dug into a mountain in southern Pennsylvania about seven miles from Camp David. It has been working since 1953 and is still an active military site. Here’s what’s on the public record.

Raven Rock at a glance

Sources for the table: the Federation of American Scientists on the dates and the official name,¹ Garrett M. Graff on the opening date,² the 2007 Federal Register rule and a 2024 township report on the location,³⁴ the Boston Globe and LIFE on the distances,⁵⁶ the Center for Land Use Interpretation on the acreage,⁷ a 2026 Washington Headquarters Services job notice on who runs it,⁸ and Graff’s interview with The War Zone on its round-the-clock staffing.⁹

Why the Pentagon wanted a hole in a mountain

The atomic bomb made a single headquarters a single target. The idea of an alternate communications centre for the armed forces goes back to 1948. When the Soviet Union tested its first atomic bomb in 1949, a protected site close to Washington for the Joint Command Post became, in the words of the FAS summary, a high priority. President Truman approved Raven Rock Mountain in 1950.¹

The thinking was simple enough. A bomb on Washington would destroy the Pentagon and everyone in it, so the military needed a second headquarters far enough away to survive and close enough to reach in a hurry. Graff, whose 2017 book is named after the bunker, told NPR that the planning “dates back to the late 1940s, right at the beginning of the atomic age”, when the government started thinking about “evacuation facilities, in case something happened to Washington”.¹⁰ Raven Rock was meant to be the alternate Pentagon, the place the military would move to under attack or the threat of one.⁹

That last clause in LIFE‘s sentence carries a lot of weight.⁶ A bunker is only useful if the right people get into it, and that problem shaped Raven Rock’s whole history, as it did the congressional shelter under the Greenbrier hotel a few years later. Everyone else, from 1961, was pointed to public fallout shelters marked with the yellow-and-black sign.

Building Site R, 1951 to 1953

The land came first. The government took land on the mountain from local owners; Graff lists, among others, 280 acres from Alfred and Georgia Holt and 45 acres from Eleanor Linebaugh.² Then the digging began in 1951.¹ Locals, Graff writes, nicknamed the unfinished tunnel “Harry’s Hole”, after President Truman.² It’s the sort of name that tells you how secret the project felt to the people living next to it.

The rock is the reason it’s there. Graff describes the builders cutting a cavern under hundreds of feet of greenstone, and notes that they liked to boast that the stone was one of the hardest rocks in the world.² James Bamford, quoted in the Boston Globe, also places the complex inside “hard greenstone granite”.⁵ Secrecy came with it. When LIFE covered the project in November 1952 it noted that photographs of the three-storey underground building were classified secret.¹¹

Site R became operational on 30 June 1953, five months after Eisenhower took office, with just over 100,000 square feet of space in Graff’s account.² The Center for Land Use Interpretation gives a slightly later date, saying the bunker came on line in 1954.⁷ We’ve gone with 1953, which matches the FAS summary and the hub page on this site.¹

What did it cost?

Nobody published an official bill that we could find, and the figures in print drift upwards as the years go by:

The 1952 LIFE item puts the bunker at Camp Ritchie in Maryland, the Army post just over the state line that supported it.¹¹ Even the FAS summary describes the site in one place as “part of Camp Albert Ritchie, Maryland”, while placing the mountain itself in Pennsylvania.¹ Read early reports with that in mind: the address on the paperwork wasn’t the address of the rock.²⁶

Inside the mountain: what is public

This section sticks to what has been published, because Raven Rock is a working military site. Nothing here comes from maps, plans or guesswork, and we haven’t tried to add any.

Graff’s description on NPR is the clearest: “a massive, hollowed-out mountain”, a “free-standing city” with “individual buildings, three-story buildings, built inside of this mountain”.¹⁰ James Bamford, quoted by the Boston Globe in 2004, counted “five buildings, each three stories tall, computer-filled caverns, and a subterranean water reservoir”.⁵ So the buildings stand inside the caverns rather than the rooms being carved out of the rock. It’s the same idea as Cheyenne Mountain, which came later.

From outside you’d see very little. The Center for Land Use Interpretation described several large concrete portals along a road around the base of the hill, with parked cars and satellite dishes, and an unmarked main entrance.¹² The Globe’s list also had a helipad, antennae, satellite dishes, a microwave tower and the two metal doors.⁵ Gizmodo’s description of “at least four stadium entrance-like portals” fits the same picture.¹³

For a safe site, the doors are the obvious question, and here we have to stop short. We couldn’t find a single published source that names the maker of Raven Rock’s blast doors or gives an official weight for them. At the Greenbrier the Mosler Safe Company’s order books survived and the figures are known; at Raven Rock the doors are still in service, and nobody’s saying. If you want to know how doors of this kind hang and seal in general, our guide to how bank vault doors work covers hinges, bolts and frames.

How big is it?

The published sizes don’t agree, probably because they measure different things in different decades:

Graff told NPR the site had been “pretty dramatically expanded” in the 15 years after 2001, which would explain some of the growth.^21412710 None of these is an official figure. The Department of Defense doesn’t publish one.

Raven Rock in the Cold War

For most of the Cold War, Site R was a standby headquarters. Graff writes that it was kept mostly in standby mode, and that it took hours to assemble the staff and bring the communications up.² The Center for Land Use Interpretation reports a full-time staff of about 350 for much of the period, with room for 2,600 more if the order came.¹² Representatives of all the military departments and the Joint Chiefs of Staff were said to be based there, as insurance against the command structure being wiped out in a nuclear war.¹⁵

It never worked alone. Fort Ritchie, a 638-acre Army post across the line in Maryland, served as the support base for Site R, with more than 2,000 employees.¹²¹⁵ Fort Ritchie closed in 1998, and much of its work passed to Fort Detrick, Maryland, from where the bunker was then administered.¹⁵⁷ Inside the mountain the Defense Information Systems Agency ran the communications and command centre; FAS lists Army, Navy and Air Force emergency operations centres there as well, with round-the-clock support.¹²¹ Some of that work was close kin to what our explainer on what a SCIF is describes: classified communications in rooms built to keep them in.

Then the Cold War ended, and so did the urgency. Graff says Raven Rock was “sort of mothballed to a certain extent during the 1990s”.¹⁰ A mountain can’t be put in a cupboard, of course, but the staff and the budget can shrink, and they did.

Timeline

• 1948 The idea of an Alternate Joint Communications Center takes shape.
• 1949 The first Soviet atomic test makes a protected site near Washington a priority.
• 1950 President Truman approves Raven Rock Mountain.
• 1951 Construction begins.
• 30 Jun 1953 Site R becomes operational.
• 1990s Partly mothballed as the Cold War ends.
• 1998 Fort Ritchie, its support base, closes; Fort Detrick takes over.
• 11 Sep 2001 Continuity plans activated; Paul Wolfowitz is sent to Site R.
• 25 May 2007 Pentagon Reservation rules, including the photography ban, take effect.

Timeline sources: FAS, Graff, NPR, the Center for Land Use Interpretation, NBC News and the Federal Register.^12101512163

9/11 and the “undisclosed location”

On the morning of 11 September 2001, Defense Secretary Donald Rumsfeld stayed at the burning Pentagon and sent his deputy, Paul Wolfowitz, to Site R.¹⁶ Bamford’s account, as the Globe summarised it, has five helicopters landing on the helipad within hours, SUVs pulling up at the main entrance and buses climbing the road, with Wolfowitz among the first to arrive.⁵ The government’s continuity of operations plan had been activated within hours of the attacks.¹²

In the months that followed, Vice President Dick Cheney kept disappearing to “undisclosed locations”. The Globe reported in 2004 that Raven Rock was one of the places he used: he set up there after the attacks and sometimes stayed there later.⁵ The Center for Land Use Interpretation called it the underground site “reportedly most favored” by Cheney, and reported that government staff were rotating through Raven Rock and Mount Weather in shifts of up to three months.¹² We’ve kept to “reported” here on purpose: none of this came from an official statement.

The bunker that had been half asleep in the 1990s was, in Graff’s words, “restarted in a hurry after Sept. 11”.¹⁰ The secret had also run out by then. A guard at the gate told the Globe’s reporter that “Everything here is classified”, but the address had been in the newspapers for years.⁵

Raven Rock today

Raven Rock is still working. It’s now an installation of Washington Headquarters Services, part of the Defense Department, and a 2026 job notice describes it as supporting “various Department of Defense (DoD) tenants in an all-hazards environment”.⁸ Graff said in 2017 that it runs “24 hours a day, 365 days a year”.⁹ Day to day, he told the Bulletin of the Atomic Scientists, the government’s bunkers are staffed by a few hundred people.¹⁷

Legally it’s part of the Pentagon. A Defense Department rule that took effect on 25 May 2007 brought the Raven Rock Mountain Complex in Adams County into the Pentagon Reservation, under an installation commander. The same rule prohibits photography, and the notice explains that it is unlawful to make “any photograph, sketch, picture, drawing, map or graphical representation” of the complex without permission.³ That’s why there’s no photograph of Raven Rock at the top of this page.

There are no tours, and Graff himself couldn’t get in while researching his book.⁹ The site does still turn up in local news now and then: in 2024 the chair of the Liberty Township planning commission told supervisors that Site R was seeking to expand.⁴ If you want a mountain vault you can actually read about in detail, the Svalbard Global Seed Vault holds seeds rather than generals and publishes far more about itself.

Raven Rock vs Mount Weather, Cheyenne Mountain and the Greenbrier

Raven Rock is the oldest of the four big US government bunkers in our guide to Cold War bunkers, which covers the whole family. Here’s how the four compare.

The differences are mostly about who each one was for and how much of it stayed secret.^118192021 Cheyenne Mountain’s buildings famously sit on 1,319 steel springs, and Raven Rock’s three-storey buildings inside the rock are its older cousin.¹⁹ The Greenbrier relied on a hotel for cover and lost its value once a newspaper printed the address. Raven Rock never had that luxury: it’s been in the press since 1952, and it’s still working.¹¹

Raven Rock in films and games

A real bunker with a name this good was always going to end up in fiction. In the video game Fallout 3, the Raven Rock Mountain Complex is the home of the Enclave, the last remnant of the United States government.¹³ We compare the games’ vaults with the real shelters in Fallout’s vaults and the history behind them. Kathryn Bigelow’s Netflix film A House of Dynamite (2025) ends with government officials heading for shelter in the complex.²² For more places where people hid valuable things in strange holes, see our list of the world’s strangest vaults.

Raven Rock myths and facts

Sources: the Federal Register and LIFE on the location, NPR on the 1990s and after, the Center for Land Use Interpretation on the tunnel rumour, and FAS and Graff on whom each bunker was for.^3111012189

Frequently asked questions