The Bifertenstock (Romansh: Piz Durschin) is a mountain in the Glarus Alps, located at an elevation of 3,419 m (11,217 ft) on the border between the cantons of Glarus (north) and Graubünden (south), its peak, however, is located about 25 metres south of the border. It overlooks four valleys: the valley of the Biferten Glacier to the north-west, the Griess Glacier to the north-east, the Val Punteglias to the south, which leads down to Trun, and the Val Frisal on the south-east. Glaciers cover both sides of the mountain, but are smaller on the southern side.
The mountain lies in the municipalities of Trun and Breil/Brigels, in the canton of Graubünden, and Glarus Süd, in the canton of Glarus. The nearest settlements are the villages of Trun, to the south, and Linthal, to the north.