Piz Sardona (or Surenstock) is a mountain in the Glarus Alps, located on the border between the cantons Glarus and St. Gallen. The 3,056 metres high mountain overlooks the valleys of Elm (Glarus) and Calfeisen (St. Gallen). Less than one kilometre south of the summit lies the tripoint (3,000 metres) between the cantons of Glarus, St. Gallen and Graubünden.