A fortress at the southern end of the Misty Mountains, centred on the tower of Orthanc, an unbreakable pinnacle of black stone built by the Numenoreans. Originally a stronghold of Gondor, it was given to the wizard Saruman as his dwelling. Saruman corrupts it into a war factory, tearing down trees and breeding Uruk-hai. Isengard is destroyed by the Ents during the War of the Ring, though the tower of Orthanc proves indestructible.