Wentworth–Coolidge Mansion is a 40-room clapboard house which was built as the home, offices and working farm of colonial Governor Benning Wentworth of New Hampshire. It is located on the water at 375 Little Harbor Road, about two miles southeast of the center of Portsmouth. It is one of the few royal governors' residences to survive almost unchanged. The site is a New Hampshire state park, declared a National Historic Landmark in 1968.