Isengard (Sindarin Angrenost, 'iron fortress') is the circular stronghold around the tower of Orthanc in Tolkien's legendarium. Held by the corrupted wizard Saruman (
萨鲁曼), it is destroyed when the Ents (
树人) flood the valley after the Battle of Helm's Deep (
圣盔谷之战). Featured prominently in The Two Towers (《
双塔奇兵》).