The Kyffhäuser (]), sometimes also referred to as Kyffhäusergebirge, is a hill range in Central Germany, shared by Thuringia and Saxony-Anhalt, southeast of the Harz mountains. It reaches its highest point at the Kulpenberg with an elevation of . The range is the site of medieval Kyffhausen Castle (Reichsburg Kyffhausen) and the 19th century Kyffhäuser Monument; it has significance in German traditional mythology as the legendary resting place of Emperor Frederick Barbarossa.