Lake Geneva boats on the lake. The lake lies on the course of the Rhône. The river has its source at the Rhône Glacier near the Grimsel Pass to the east of the lake and flows down through the canton of Valais, entering the lake between Villeneuve and Le Bouveret, before flowing slowly towards its egress at Geneva. Other tributaries are La Dranse, L'Aubonne, La Morges, La Venoge, La Vuachère, and La Veveyse. Lake Geneva is the largest body of water in Switzerland, and greatly exceeds in size all others that are connected with the main valleys of the Alps. It is
Swiss Alps on the shores of Lake Geneva to Rorschach on the shores of Lake Constance, passing close to the cities of Thun and Lucerne. The not well defined regions in Switzerland that lie on the margin of the Alps, especially those on the north side, are called the "Swiss Prealps" ("Préalpes" in French, "Voralpen" in German, "Prealpi" in Italian). The Swiss Prealps are mainly made of limestone and they generally do not exceed . The Alpine cantons (from highest to lowest) are Valais, Bern, Graubünden, Uri, Glarus, Ticino, St. Gallen, Vaud, Obwalden, Nidwalden, Schwyz, Appenzell Innerrhoden, Appenzell Ausserrhoden, Fribourg, Lucerne and