The Mount Weather Emergency Assistance Center is a secret United States government fortress in Bluemont, Virginia that is designed to house the American government in the case of nuclear warfare. The base is located inside a hollowed-out mountain and can purportedly withstand a nuclear blast.

It is a central part of the American Continuity of Operations Plan, and some have suggested the base contains a fully operational Congress and White House, ready to be used in an emergency.

Not much hard information is known about Mount Weather, and many of the stories about its operation are conflicting and vauge. Some say the mountain contains an entire city, while others say it is just a simple army-type base. The American government has not revealed much information about Mount Weather to date, although it has acknowledged its basic existence and stated purpose.