New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. It is bordered on the north and east by the U.S. state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania, and on the southwest by Delaware. New Jersey is the 4th least extensive, but the 11th most populous and the most densely populated of the 50 United States. New Jersey lies mostly within the sprawling metropolitan areas of New York City and Philadelphia.