Minas Morgul
By the time of "The Lord of the Rings", the stone of Orthanc was in the hands of the wizard Saruman, while the stone of Minas Ithil, (by then Minas Morgul, the city of the Nazgûl), had been taken by Sauron. That of Minas Tirith remained in the hands of the Steward of Gondor, Denethor. The stone of Osgiliath had been lost in the Anduin when the city was sacked.