Raven Rock Site R is a facility of the United States military facility that lies on Pennsylvania's southern border, nearby Washington DC, and built into the Raven Rock mountain. The facility is currently (2002) home to the Alternate Joint Communications Center, which is designated a 'disaster recovery site' for military communications operations and the National Command Authority.

For the extent of Site R's life, 'disaster' has been a pleasant euphemism for nuclear war. The idea for the Alternate Joint Communications Center was had in 1948, and construction of Site R was approved by the Truman administration in 1949, after the Soviet Union detonated their first nuclear device.

Little is known about the actual makeup of the Site R facility, or its present state of affairs (because of the level of secrecy that surrounds it), but it has been reported by local residents to have been the secret facility that Vice President Dick Cheney used for several months after the September 11 attacks. Cheney's former secret location has not been officialy revealed.