Within the New York City metropolitan area, the airport system—which includes John F. Kennedy International Airport, LaGuardia Airport, Newark Liberty International Airport (located in New Jersey), Stewart Airport and a few smaller facilities—is one of the largest in the world. The Port of New York and New Jersey, which includes the waterways around New York City and its metropolitan area, is one of the busiest seaports in the United States. There are also three commuter rail systems, the PATH rapid transit system to New Jersey, and various ferries between Manhattan and New Jersey.