Bosruck, mountain in Upper Austria/Styria, alt. 1992 m, mainly limestone, westernmost part of the Ennstal Alps, dominates the Upper Enns valley, flanked by the Pyhrnpass (alt. 954 m) and the Pyhrgasgatterl passes (alt. 1,508 m). A train tunnel (Pyhrnbahn) and a motorway tunnel run through the massif between Spital am Pyhrn and Ardning, connecting Upper Austria with Styria.