Lake Geneva is divided into three parts because of its different forms of formation (sedimentation, tectonic folding, glacial erosion): According to the Swiss Federal Office of Topography, swisstopo, "Lac de Genève" designates that part of the "Petit Lac", which lies within the cantonal borders of Geneva (excluding the cantonal exclave Céligny), so about from Versoix–Hermance to the Rhône outflow in Geneva. The Chablais Alps border is its southern shore, the western Bernese Alps lie over its eastern side. The high summits of Grand Combin and Mont Blanc are visible from some places. Compagnie Générale de Navigation sur le lac Léman (CGN) operates
Swiss Plateau the southwest, the Swiss Plateau is confined by Lake Geneva, in the northeast, by Lake Constance and the Rhine. Geologically, the Swiss Plateau is part of a larger basin that extends beyond the border of Switzerland. At its southwestern end, in France, the plateau, in the Genevois, ends at Chambéry where Jura and Alps meet. At the other side of the Lake Constance, the plateau continues in the German and Austrian Pre-Alps. Within Switzerland, the Swiss Plateau has a length of about , and its width increases from the west to the east: In the Geneva region, it is about