Trenton is the capital city of New Jersey, and is one of the major cities of BosWash. In the 2000 US census, the city's population was estimated to be over 9000. Until 1999, Trenton was considered an anchor city of the Philadelphia Metropolitan Area. However, Trenton was redesignated as an anchor city of the New York Metropolitan Area in 2000. Trenton is served by the Trenton Municipal Airport, the Greyhound bus line, and Amtrak railways.