The United States has 22 Air Route Traffic Control Centers (ARTCC).[1] They are operated by and are part of the Federal Aviation Administration of the U.S. Department of Transportation. An ARTCC controls aircraft flying in a specified region of airspace, known as a flight information region (FIR), typically during the en route portion of flight. The purpose of control is to promote the safe, orderly, and expeditious flow of air traffic[2] and prevent collisions. In countries other than the U.S., such a facility is generally known as an area control center.
Air Route Traffic Control AVweb