The Airtrain has three major stations within the airport, one for each main terminal (A, B, and C). There are four other stations (P1, P2, P3, and P4) for the parking lots and rental car facilities plus an eighth at the Northeast Corridor.
Newark [1] is New Jersey's largest city, located on the west side of the Hudson River close to New York.
There exists a Newark, New York but is is a small rural town in central New York state so don't make the mistake of addressing someone in Newark, NY if what you are looking for is in the Newark close to New York City.
Newark Penn Station is also the city's bus terminal and is served by NJ Transit buses, as well as Greyhound and others.