The Raven Rock Mountain Complex (RRMC), also known as Site R, is a U.S. military installation with an underground nuclear bunker near Blue Ridge Summit, Pennsylvania, at Raven Rock Mountain that has been called an "underground Pentagon". The bunker has emergency operations centers for the United States Army, Navy, Air Force and Marine Corps. Along with Mount Weather Emergency Operations Center in Virginia and the Cheyenne Mountain Complex in Colorado, it formed the core bunker complexes for the US continuity of government plan during the Cold War to survive a nuclear attack. Description The installation's largest tenant unit is the Defense Threat Reduction Agency, and RRMC communications are the responsibility of the 114th Signal Battalion. The facility has 38 communications systems, and the Defense Information Systems Agency provides computer services at the complex. History Raven Rock Mountain is adjacent to Jacks Mountain on the north while Miney Branch flows west-to-east between them in the Potomac River Watershed. The 1820 Waynesboro-Emmitsburg Turnpike with toll station for the 1787 crossroad was constructed between the mountains, where the Fight at Monterey Gap was conducted after the 1863 Battle of Gettysburg (Stuart's artillery at Raven Rock Gap shelled Federal troops.) In 1870, copper ore was discovered to the north, and the nearby Fountain Dale Springs House was established in 1874. The scenic area's mountain recreation facilities to the west included the 1877 Pen Mar Park, the 1878 High Rock Tower, the 1885 Monterey Country Club, and several resorts (e.g., Blue Mountain House, Buena Vista Springs Hotels, & Washington Cliff House). The 1889 Jacks Mountain Tunnel on the Western Extension (Baltimore and Harrisburg Railway) was completed near Raven Rock Mountain, and nearby stations were at Blue Ridge Summit and Charmian. The Army's 1942 Camp Ritchie was built southwest of the resorts, and a local road was built eastward from Blue Ridge Summit and intersected the north-south Fountaindale-Sabillasville Road (the intersection now provides access to the RRMC main gate.) Planning for a protected Cold War facility near Washington, D.C. began in 1948 for relocation of military National Command Authorities and the Joint Communications Service. Underground communications center The planned deep underground communications center was identified in the original 1950 federal petition to seize the Beard Lot, a 1,500-foot-high, mile-long hill located at Fountaindale and extending east and south along the Waynesboro-Emmitsburg road, The "Declaration of Taking" for United States of America v. 1,100 Acres of Land