Legal Question in Employment Law in New Jersey

Did the HR Department give you a reason? My guess is that it has to do with either the benefits package - the insurance may not cover you in Maryland - or for reasons having to do with the type of work you do. You should request an explanation and the company's position might make sense once you hear it.

As for the legality of their position, New Jersey is an employment-at-will state and unless you have an employment contract, the employer can terminate you at any time for any or no reason (and you can quit on the same basis) - provided the employer's action is not in violation of the federal and state laws prohibiting discrimination. You should talk with an employment lawyer to review the specific facts of your matter and understand your legal rights.