Taken from the book "Bigger Secrets" by William Poundstone, published 1986 ISBN 0-395-38477X

      "In the best-selling 1962 spy thriller SEVEN DAYS IN MAY, the Joint Chiefs of Staff plot to overthrow the U.S. president. Their conspiracy centers on a place called Mount Thunder, a secret subterranean command post where government leaders would go in the event of a nuclear attack.
      On December 1, 1974, a TWA Boeing 727 jet crashed into a fog-shrouded mountain in northern Virginia and burned, killing all ninety-two persons aboard. Near the wreckage was a fenced government reserve identified as Mount Weather.
      Mount Weather is a real place; eighty-five acres located forty-five miles west of Washington and 1,725 feet above sea level, near the town of Bluemont, Virginia. In the event of all-out war, an elite of civilian and military leaders are to be taken to Mount Weather's cavernous underground shelter to become the nucleus of a postwar American society. The government has a secret list of those persons it plans to save.
      The Federal Emergency Management Agency (FEMA) runs Mount Weather. When it has to talk about the place, which is rare, it calls it the "special facility." Its more common name comes from a weather station that the U.S. Department of Agriculture had maintained on the mountain.
      The authors of SEVEN DAYS IN MAY, Fletcher Knebel and Charles W. Bailey II, were Washington journalists who learned a lot about the then-quite-secret post. Few readers of Knebel and Bailey's fiction could have imagined how close to the truth it was. The novel gives detailed highway directions from Washington:

  ...the Chrysler wheeled onto Route 50,
  heading away from Washington....
  In the jungle of neon lights and access
  roads at Seven Corners, Corwin saw Scott bear
  right onto Route 7, the main road to Leesburg.
  The two cars moved slowly through Falls Church
  before the traffic began to thin out and speed
  up....
   At the fork west of Leesburg, Scott bore
  right on Route 9, heading toward Charles
  Town.... They began to climb toward the Blue
  Ridge, the eastern rim of the Shenandoah
  Valley....
   West of Hillboro, where the road crossed
  the Blue Ridge before dropping into the
  valley....Scott turned left. Corwin followed
  him onto a black macadam road that ran
  straight along the spine of the ridge.
   ...Because of his White House job, Corwin
  knew something about this road that few other
  Americans did. Virginia 120 appeared to be
  nothing more than a better-than-average Blue
  Ridge byway, but it ran past Mount Thunder,
  where an underground installation provided one
  of the several bases from which the President
  could run the nation in the event of a nuclear
  attack on Washington.

      Knebel and Bailey disguised the directions slightly. You continue on Route 7 west of Leesburg, turning left on Route 601 just west of Bluemont. It's Virginia Route 601 that runs right up to the gates of Mount Weather. Residents have long known there is something funny about that road; it is always the first road cleared after a snowstorm.
      At one point, the government asked the local paper not to print any articles about the facility. But it is all but impossible to keep such a place secret. The Appalachian Trail runs right by Mount Weather, and hikers can get close enough to see signs and flashing lights. One sign reads: "All persons and vehicles entering hereon are liable to search. Photographing, making notes, drawings, maps or graphic representations of this area or its activities are prohibited." In the late 1960s an unidentified "hippie" is supposed to have stumbled upon the facility and sketched it from a tree. His drawing turned up in the QUICKSILVER TIMES, an underground newspaper in Washington.
      Residents also tell of the time a hunt club chased a fox onto the site and triggered an alarm. The club had to go to the main gate to get the dogs back.
      After the TWA crash, a spokesman "politely declined to
comment on what Mt. Weather was used for, how many people work there, or how long it has been in its current use," the WASHINGTON POST reported. The POST published a picture of the facility, citing far-fetched speculation that Mount Weather's radio antennas may have interfered with the jet's radar and caused the disaster.
      You don't get into Mount Weather without an invitation. The entrance is said to be like the door to a bank vault, only thicker, set into a mountain made out of the toughest granite in the East. It is guarded around the clock.
      Mount Weather got more unsolicited publicity in 1975. Senator John Tunney (D-Calif.) charged that Mount Weather held dossiers on 100,000 or more Americans. A sophisticated computer system gives the installation access to detailed information on the lives of virtually every American citizen, Tunney claimed. Mount Weather personnel stonewalled question after question in two Senate hearings.
      "I don't understand what they're trying to hide out there," Douglas Lea, staff director of the Senate Subcommittee on Constitutional Rights, said. "Mount Weather is just closed up to us." Tunney complained that Mount Weather was "out of control."
      Mount Weather has been owned by the government since 1903, when the site was purchased by the U.S. Department of Agriculture. Calvin Coolidge talked about building a summer White House there. In World War I it was an artillery range, and during the Depression it was a workfarm for hobos. Mount Weather as an alternate capital seems to have been the idea of Millard F. Caldwell, former governor of Florida.
      There is a fallout shelter under the East Wing of the White House. No one believes it offers any real protection from a nuclear attack on Washington, however. FEMA has elaborate plans for getting the president and other key officials out of Washington should there be a nuclear attack.
      In that event, the president is supposed to board a Boeing 747 National Emergency Airborne Command Post ("Kneecap"). That is presumed to be safer than any point on the ground. The president's plane can be refueled in the air from other planes and may be able to stay airborne for as long as three days. Then its engine will conk out for lack of oil. That is where Mount Weather comes in.
      Government geologists selected the site because it has some of the most impregnable rock in the United States. The shelter was started in the Truman administration, and it took years to tunnel into the mountain.
       There is a whole chain of shelters for leaders and critical personnel. The Federal Relocation Arc, a system of ninety-six shelters for specific U.S. Government agencies, sweeps through North Carolina, Virginia, West Virginia, Maryland, and Pennsylvania. A duplicate of the Pentagon is located at a site called Raven Rock in Maryland. The administrative center of the whole system, and the place where the top civilians would go, is Mount Weather.
      Mount Weather is much more than a fallout shelter; it is a troglodytic Levittown. In the mid-1970s Richard Pollack, a writer for PROGRESSIVE magazine, interviewed a number of persons who had been associated with Mount Weather. According to them, Mount Weather is an underground city with roads, sidewalks, and a battery-powered subway. A spring-fed artificial lake gleams in the fluorescent light. There are office buildings, cafeterias, and hospitals. Large dormitories are furnished with bunks or "hot cots" -- hammocks intended to be occupied in three eight-hour shifts. There are private apartments as well. Mount Weather has its own waterworks, food storage, and power plant. A "bubble-shaped pod" in the East Tunnel houses one of the most powerful computers in the world.
      The Situation Room, a circular chamber, would be a nerve center in the time of war. The Mount Weather folks set great store by visual aids and retain artists and cartographers at all times. A futuristic color videophone system is the basic means of communication within Mount Weather's subterranean world. "All important staff meetings were conducted via color television as far back as 1958, long before it was generally available to the public," one former staffer bragged.
 The most surprising of Pollack's revelations is that Mount Weather has a working back-up of U.S. Government EVEN NOW. Undisclosed persons there duplicate the responsibilities of our elected leaders, making Mount Weather an eerie doppelganger of the United States.
      An Office of the Presidency is ensconced in an underground wing known as the White House. The elected president or survivor closest in the chain of command would make his way there and take over the reins. Until then, a staffer appointed by FEMA would be carrying out duties said to simulate those of the real president.
      Installed at Mount Weather are nine federal departments, their very names ironic in the context: Agriculture, Commerce, Health and Human Services, Housing and Urban Development, Interior, Labor, State, Transportation, and the Treasury. Miniature versions of the Selective Service, the Veteran's Administration, the Federal Communications Commission, the Post Office, the Civil Service Commission, the Federal Power Commission, and the Federal Reserve are there, too.
      "High-level government sources, speaking under the promise of strict anonymity, told me that each of the federal departments represented at Mount Weather is headed by a single person on who is conferred Cabinet-level official," Pollack reported. "Protocol even demands that subordinates address them as 'Mr. Secretary.' Each of the Mount Weather 'Cabinet members' is apparently appointed by the White House and serves an indefinite term. Many of the 'secretaries' have held their positions through several administrations."
      What do all these people DO? Twice a month, Mount Weather stages a war game to train its personnel and explore various dire scenarios. Once a year they pull out all the stops and have a super drill in which REAL Cabinet members and White House staffers fly in from Washington.
      General Leslie Bray, director of the Federal Preparedness Agency, FEMA's predecessor, told the Senate that Mount Weather has extensive files on "military installations, government facilities, communications, transportation, energy and power, agriculture, manufacturing, wholesale and retail services, manpower, financial, medical and educational institutions, sanitary facilities, population, housing shelter, and stockpiles." Additional information is kept in safekeeping at other shelters in the Federal Relocation Arc.
      There is a body of opinion that considers Mount Weather obsolete. Mount Weather is a non-movable target, and a very strategic one if the relocation works. The "toughest granite in the East" may have offered some protection in Eisenhower's time, but multiple strikes could blast the mountain away. It was reported that the TWA jet crash knocked out power at Mount Weather for two and a half hours. What would a bomb do?
      The Soviet Union knows exactly where Mount Weather is -- and almost certainly knew long before the Western press did. The Soviets tried to buy an estate near Mount Weather as a "vacation retreat" for embassy employees. The State Department stopped the sale.