Cornštejn Castle (Czech: hrad Cornštejn or Cornštýn, Corštejn, Corštýn, German: Zornstein) is a castle near Bítov, 31 kilometres (19 mi) west of Znojmo, in south-west Moravia, the Czech Republic. Surrounded by magnificent landscape of the Dyje (Thaya) River Valley, Cornštejn Castle stands on a strategic location, not far from an Eneolithic fortified settlement. Though in ruins now, it still shows what a lofty medieval residence and fortress it once was. The Dyje (Thaya) River, now impounded by , flows around the castle in a big meander. The name of the castle is derived from German "Zorn" (anger) and "Stein" (stone).