The C area encompasses the airspace from the Cascade Mountains to Western Montana and from the Canadian border south into northeastern Oregon. It is made up of three low altitude sectors (8, 9, and 18), controlling below 24,000 ft. and four high altitude sectors (7, 11, 47, and 48), which control the airspace 24000 ft.  and above.  Three Approach Control facilities operate within the C Area. Spokane Approach is a 24-hour operation covering Spokane International Airport , Fairchild Air Force Base, Felts Field, Couer D’ Alene Air Terminal, and Deer Park Airport. Chinook Approach and Grant County Approach Controls operate from 6am to 10pm daily. Chinook encompasses Yakima, Pasco, Walla Walla and Richland Airports in Washington as well as Pendleton and Hermiston Airports in Oregon. Grant County Approach serves Moses Lake and Ephrata airports in Washington State.  It serves as a major training support facility for Air Force and Navy tactical training and for Boeing flight test operations. The C Area controls the airspace contained within both Grant County and Chinook Airspace after these facilities close at night.  The C Area contains a great deal of Special Use Airspace for military operations. Specially assigned airspace and are used for activities such as air refueling, terrain following, air combat maneuvers, armor, artillery, and air/ground fire exercises.  The majority of the C Area’s commercial air traffic passes through its high altitude sectors, to and from Seattle, WA and Vancouver, B.C. International polar traffic between Europe and San Francisco or Los Angeles also traverses the C area.