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
Chensagi River West mid-May, however, safe ice circulation is generally from mid-November to mid-April. The main hydrographic slopes near the Chensagi West River are: The Chensagi River originates at the mouth of a small unidentified lake (length: ; altitude: ). The mouth of this head lake is located at: From the mouth of the head lake, the "Chensagi River West" flows over according to the following segments: The "West Chensagi River" flows on the north bank of the Chensagi River which generally flows southwestward across Chensagi Lake to a bay in the northwest of Lake Maicasagi. The latter in turn flows Southwesterly through