Rockingham is a historic house that was the home of John Berrien (1711–1772) and George Washington's final headquarters of the Revolutionary War. It is located at 84 Laurel Avenue, Franklin Township in Somerset County, New Jersey. The house was originally located on the hillside east of the Millstone River at Rocky Hill. It has been moved within southern Franklin Township several times, and is now closer to Kingston than to Rocky Hill. The residence is a featured part of the Millstone River Valley Scenic Byway. The oldest portion of the house was built as a two-room, two-story saltbox style house c. 1710; a kitchen and additional rooms were added on in the early 1760s, expanding with the Berrien family. The first reference to the house as "Rockingham" does not appear until a 1783 newspaper