penal colony

penal colony
    n 1: a penal institution where prisoners are exiled (often
         located on an island from which escape is difficult or
         impossible)
    

45 Moby Thesaurus words for "penal colony":
      POW camp, bastille, black hole, borstal, borstal institution,
      bridewell, brig, cell, concentration camp, condemned cell,
      death cell, death house, death row, detention camp, federal prison,
      forced-labor camp, gaol, guardhouse, house of correction,
      house of detention, industrial school, internment camp, jail,
      jailhouse, keep, labor camp, lockup, maximum-security prison,
      minimum-security prison, oubliette, pen, penal institution,
      penal settlement, penitentiary, prison, prison camp, prisonhouse,
      reform school, reformatory, sponging house, state prison, stockade,
      the hole, tollbooth, training school