The longest section of the sixth and final stage of the Karwendel Höhenweg trail leads mountaineers along the Isar. This river has its source in Tirol and only enters Germany after passing through Scharnitz.
Good to know: Contrary to what many visitors assume, the source of the Isar river is not a true spring as such but rather the point at which three streams converge to form the Isar. These streams are fed by the cirque sources with water from the gravelly drainage basin located further up. Their turquoise hue forms a beautiful contrast with the light grey to white gravel, providing a delightful sight for mountaineers as they hike along the final stage from the Hallerangerhaus to Scharnitz.
After leaving the Hallerangerhaus, you follow trail 224 heading west. (Detour to Sunntigerspitze mountain: follow the sparsely marked trail leading north from the Hallerangeralm.)You pass the Kohleralm pasture hut and soon come to the Lafatscher Niederleger hutbefore making a somewhat more steep descent on the road down into the Hinterautal valley. You can reach the Kastenalm mountain hut by taking a brief detour at the marked fork in the road. From here, you keep heading along the road out of the valley and pass the source of the Isar river on the way. This is followed by a gentle ascent to the panoramic Gleirschhöhe (1069 m) and a leisurely descent that takes you past the Gasthof Wiesenhof inn. You then come to the Isarbrücke bridge and subsequently complete the route in Scharnitz. As an alternative to covering the whole distance on foot, you can pay to hire a bicycle from the Hallerangerhaus hut and save yourself some time during the descent (between the Kastenalm and Scharnitz).