Boston Air Route Traffic Control Center (ZBW; in radio communications, "Boston Center") is one of 22 Air Route Traffic Control Centers in the United States, located in Nashua, New Hampshire. The primary responsibility of ZBW is the separation of overflights, and the expedited sequencing of arrivals and departures along STARs (Standard terminal arrival routes) and SIDs (Standard instrument departures) for the Boston Metropolitan Area, the New York Metropolitan Area, and other areas in the Northeast region of the United States.