NORAD, the North American Aerospace Defense Command, is a partnership of Canadian and American military who, since 1958, have protected the skies over Alaska, Canada, and the contiguous United States. NORAD uses radar, airborne radar, satellites, fighter aircraft, command structures, and intelligence capabilities to enforce control of North American airspace. The facility is housed on the main level of the Cheyenne Mountain Complex in Colorado, 28 floors above the stargate, and NORAD and the SGC remain in contact whenever an alien threat is detected in the skies above North America.
Cross Reference: Cheyenne Mountain Complex, Colorado Springs, SGC
Episode Reference: Secrets, A Matter of Time, Nemesis, Ex Deus Machina, Insiders