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Raven Rock Mountain Complex (RRMC), commonly called Site R or “the Rock,” is tunneled into Raven Rock Mountain near Blue Ridge Summit/Fountaindale in south‑central Pennsylvania, close to Camp David and within relocation distance of Washington, D.C.whitehouse.gov1+3
Its primary mission is to support the Continuity of Operations Plan for the Office of the Secretary of Defense and the Joint Staff, functioning as a backup command center to the Pentagon.veteran+2
The site houses emergency operations centers for the Army, Navy, Air Force, Marine Corps, and joint command/communications functions.publicintelligence+2
The concept was approved by President Harry S. Truman in 1950, in the early Cold War, as a secure relocation site for Pentagon leadership against the threat of Soviet nuclear attack.greydynamics+2
The government seized a roughly 1,500‑foot‑high area at Fountaindale, Pennsylvania, then began blasting out super‑hard greenstone granite in 1951; about half a million cubic yards of rock were removed in roughly ten months.whitehouse.gov1+2
Construction of three underground buildings was substantially complete by 1953, with the complex officially entering operation that year, though the project suffered accidents, worker deaths, strikes, and cost overruns that drove spending to around 35 million dollars by 1954.wikipedia+1
During the Cold War it was integrated into the broader continuity‐of‑government architecture alongside Cheyenne Mountain (NORAD) and Mount Weather in Virginia.nationalinterest+3
Inside the hollowed‑out mountain sit multiple three‑story, office‑like buildings built in large caverns; open areas accommodate internal roads and parking for trucks and buses.atlasobscura+3
The installation is designed to be self‑sufficient, with dual power plants for electricity, multiple underground water reservoirs, food stores, and a sophisticated ventilation and air‑filtration system.greydynamics+2
Descriptions note two underground reservoirs, power generation, and even amenities such as a fully stocked bar, reflecting its design as a long‑term living and working environment for hundreds to thousands of people.atlasobscura+1
Buildings sit on large springs and the rock walls are bolted and regularly inspected to withstand shock and vibration; the facility can operate sealed (“buttoned‑up”) for at least about 30 days and accommodate on the order of 3,000 personnel in an emergency.wikipedia+2
Electric vehicles are used inside the complex for internal transportation.whitehouse.gov1
RRMC functions as an alternate joint communications and command center (often called the Alternate Joint Communications Center, AJCC) and a disaster‑recovery site for high‑level defense communications centers.publicintelligence+2
It supports around‑the‑clock operations, with facilities that plan, install, operate, and maintain dozens of communications systems including switching, transmission, data distribution, visual information, and power generation infrastructure.publicintelligence
The complex hosts emergency operations centers for the individual services as well as joint staff components, tied into secure worldwide networks so that national command authorities can issue orders and coordinate military operations if primary sites are unusable.wikipedia+2
While built with nuclear war in mind, RRMC has been used or activated in other crises; for example, Vice President Dick Cheney spent time there after the 11 September 2001 attacks as part of continuity‑of‑government measures.npr+1
In peacetime, only a relatively small permanent staff (on the order of a hundred personnel) is reported to be stationed there regularly, with the ability to surge to thousands in an emergency.veteran
Open sources indicate that Raven Rock remains operational in the 21st century as one of several still‑maintained government bunkers intended for extreme contingencies.nationalinterest+2
The existence of the facility became more widely known through declassified documents, reporting, and works like Garrett Graff’s book Raven Rock, yet detailed day‑to‑day operations, current staffing, and exact capabilities remain highly classified.npr+2
The site itself is closed to the public, with access controlled by the military; most of what is known comes from historical records, limited official descriptions, and investigative journalism rather than contemporary on‑site observation.veteran+4
If you’d like, I can zoom in on a particular angle—architecture and engineering details, Cold War planning uses, or how it fits into today’s continuity‑of‑government system.