100th Missile Defense Brigade (Ground-based Midcourse Defense), known as 100th MDB (GMD), is a multi-component (meaning both Title 10 and Title 32) Army National Guard brigade headquartered at Schriever Air Force Base, Colorado. It has component formations located in Fort Greely, Alaska, Vandenberg Air Force Base, California, and Fort Drum, New York manned by national guardsmen of the 49th Missile Defense Battalion, 100th MDB, Detachment 1, and 100th MDB, Detachment 2 in Alaska, California, and New York, respectively, on a round-the-clock 24/7/365 basis. 100th MDB (GMD) is part of the United States Army Space and Missile Defense Command.