The Urnersee occupies the northernmost and deep portion of the great cleft of the Reuss Valley, which has cut through the Alpine ranges from the St Gotthard Pass to the neighbourhood of Schwyz. From its eastern shore the mountains rise in almost bare walls of rock to a height of from above the water. The two highest summits are the Fronalpstock and the Rophaien (2078 m). Between them the steep glen or ravine of the Riemenstaldener Tal descends to Sisikon, the only village with Flüelen right on the shore on that side of the Urnersee. On the opposite or western shore, the mountains attain still greater dimensions. The Niederbauen Chulm is succeeded by the Oberbauenstock, and farther south, above the ridge of the Scharti, appear the snowy peaks of the Gitschen and the Uri Rotstock (2,928 m). In the centre opens the Reuss Valley, backed by the rugged summits of the Urner and Glarner Alps.