This graphic shows the boundaries of the 20 Air Route Traffic Control Centers (ARTCCs) that cover the airspace of the U.S. 48 contiguous states. Also depicted is the Denver ARTCC airspace showing the Denver TRACON in middle and the primary approach routes into the Denver TRACON. In addition, a drawing of the Denver TRACON airspace is shown with the Denver airport near the center of the TRACON and the primary approach routes used in a west flow configuration.