Mount Weather (1954-59, Bluemont VA): FEMA civilian COG. ~600-700K sq ft subterranean. 'Operation High Point' construction code name. Continuously staffed since 9/11.
Raven Rock / Site R (1951-53, PA/MD border): military COG. Excavated from greenstone granite; 500K cubic yards of spoil. 5 three-story buildings inside the cavern. 3,000 personnel, 30 days 'buttoned-up' self-sufficient. Cheney dispatched here 9/11.
Cheyenne Mountain Complex (1961-66, CO): NORAD. $142.4 million initial cost ($66 million for ops center + equipment). Granite excavation. Buildings on massive springs to absorb nuclear shockwave. Remains active hardened alternate command center.
Project Greek Island / Greenbrier (1959-62, WV): Congressional COG. Classified 30 years; declassified 1992 by Washington Post. The canonical proof that massive covert COG facilities can be constructed beneath active civilian commercial centers.
PEOC (White House East Wing): Presidential Emergency Operations Center. Used Sept 11 2001 by Cheney + key staff. Immediate executive-branch relocation point.
PINDAR / Q-Whitehall (London UK, 1984-92): UK MOD bunker ~200 ft below street level. £126.3M. Houses 400 senior political + military leaders. Interfaces with Permanent Joint Headquarters at Northwood.