New Castle is the smallest town in the state of New Hampshire. It is located in Rockingham County on islands at the mouth of the Piscataqua River. The town occupies an archipelago which is made up of a main island known as Great Island and several smaller ones surrounded by the Atlantic Ocean and Piscataqua River. The town of Newcastle is connected to the mainland by bridges. The town occupies an area of about 2.4 square miles and has a population of about 1000. Originally chartered as a county of Portsmouth, the town was named Newcastle in 1693 after the defensive fort.
Among the sites of interest in the town are Fort Stark, Fort Constitution and the Wentworth by Sea. Fort Constitution was built to protect the Portsmouth Harbor together with six other forts. These forts were originally meant to protect the colonists. In succeeding years the forts were refortified to face new challenges following the Spanish American War. Currently both Fort Constitution and Fort Stark are obsolete and serve as historic sites. Fort Stark is open by appointment and there are trails to explore the fort area. The Wentworth by Sea is a historical attraction due to the fact that it hosted the negotiation talks that ended the Russo-Japanese war in 1905. The treaty of Portsmouth was signed at this hotel marking the end of hostilities. The peace talks between the warring nations were mediated by Theodore Roosevelt who was then president of the United States and consequently won the Nobel Peace Prize for his efforts.