Seavey's Island side of Seavey's Island at the former site of Camp Long, a stockade named for Secretary of the Navy John Long, where 1,612 prisoners of war from the Battle of Santiago de Cuba were confined from July 11 to mid-September 1898 during the Spanish–American War. Camp Heywood, a Marine camp named after Colonel Charles Heywood, was located just north of the naval prison. It was occupied after the 1st Battalion's return from Cuba in late August until September 21, 1898. According to the National Trust for Historic Preservation, the Portsmouth Naval Shipyard has 62 buildings listed on the National Register
Battle of Santiago de Cuba sued for peace. Spain surrendered in August and the war was over. Some of the terms of surrender were as follows: These terms, upon which both sides came to an agreement during the 1898 Treaty of Paris (1898) negotiations, decided the fate of the remaining Spanish troops, vessels, and the matter of Cuba's sovereignty. Spanish prisoners of war that were not wounded were sent to Seavey's Island at the Portsmouth Naval Shipyard in Kittery Maine, where they were confined at Camp Long from July to September 1898. The Americans treated Spain's officers, soldiers, and sailors with great respect. Ultimately, Spanish