New Jersey is a state situated within both the Mid-Atlantic and Northeastern regions of the United States. It is the most densely populated of all 50 U.S. states, and is situated at the center of the Northeast megalopolis. New Jersey is bordered on its north and east by New York state; on its east, southeast, and south by the Atlantic Ocean; on its west by the Delaware River and Pennsylvania; and on its southwest by Delaware Bay and Delaware. At 7,354 square miles (19,050 km2), New Jersey is the fifth-smallest state in land area, but with close to 9.3 million residents as of the 2020 United States census, its highest decennial count ever, it ranks 11th in population. The state capital is Trenton, and the state's most populous city is Newark. New Jersey is the only U.S. state in which every county is deemed urban by the U.S. Census Bureau with 13 counties included in the New York metropolitan area, seven counties in the Philadelphia metropolitan area, and Warren County part of the heavily industrialized Lehigh Valley metropolitan area.

The Mid-Atlantic is a region of the United States located in the overlap between the Northeastern and Southeastern states of the United States. Its exact definition differs upon source, but the region typically includes Delaware, the District of Columbia, Maryland, New Jersey, New York, Pennsylvania, Virginia, and West Virginia with other sources including or excluding other states or areas in the Northeast and Southeast. The region has its origin in the Middle Colonies of the 18th century, its states being among the Thirteen Colonies of pre-revolutionary British America. As of the 2020 census, the region had a population of 60,783,913, representing slightly over 18% of the nation's population.