If you have ever been driving around New Castle, New Hampshire, you have surely seen the Portsmouth Naval Prison. This massive abandoned building is architecturally stunning and it can be found on the island where the Portsmouth Naval Shipyard is located. The building was constructed on the former grounds of Camp Long between 1905 and 1908 by the military. Architects modeled the prison after Alcatraz considering it was set on an island and would use tidal currents to deter escape. In 1918, the prison reached its maximum capacity of 2,295. From 1942-1943, new wings were added to both sides of the prison to expand the occupancy capacity to 3,088. The prion remained active through World War 1, World War 2, the Korean War, and the Vietnam War.

After holding over 85,000 military inmates over its 66 years of usage, the prison closed down in 1974. Some military exercises were held inside the prison throughout the 1980s, but after those, the building was abandoned. The prison is often referred to as the “Alcatraz of the East” along with “the Fortress” and it can be viewed from Portsmouth Avenue in New Castle today. No visitors are allowed to visit the prison considering the island is still an active Naval Shipyard and official credentials are required to enter.

If you love exploring abandoned locations, be sure to check out the abandoned coastal gun batteries at Fort Stark down the road. These include Battery Alexander Hays, Battery Edward Kirk, Battery David Hunter, and Battery William Lytle.