Bastøy Prison (Norwegian: Bastøy landsfengsel) is a minimum-security prison on Bastøy Island, Norway, located in the Horten municipality about 75 kilometres (46 mi) south of Oslo. The prison is on a 2.6 square kilometre (1 sq mi) island and hosts 115 inmates. Arne Kvernvik-Nilsen, governor of the prison, leads a staff of 69 prison employees. Of this staff, only five employees remain on the island overnight.