Geneva, Lake

Geneva, Lake, also Lac Léman or Lake Leman (German, Genfersee), largest lake in central Europe, about 583 sq km (225 sq mi) in area, straddling the border between Switzerland and France. The largest part of the lake, about 363 sq km (140 sq mi), is in western Switzerland. The two most populous lakeside cities, Geneva and Lausanne, are in Switzerland; on the French side are the notable spas Thonon-les-Bains and Évian-les-Bains. Shaped like a crescent, the lake lies about 380 m (1,250 ft) above sea level. It is 72 km (45 mi) long, varies from about 2.4 to 13 km (1.5 to 8 mi) in width, and has a maximum depth of about 310 m (1,015 ft). The Rhône River enters the lake at its eastern end and issues from it at the western extremity; the deposits of the Rhône at its point of issue have contracted the lake area considerably, towns and villages once on the shore now being miles inland. About 20 small streams flow into the lake, which is surrounded by the Alps on the south and east and the Jura Mountains on the north and west. Lake Geneva is frequently subject to the phenomena known as seiches, which occasion a rise and fall of about 0.6 to 1.5 m (2 to 5 ft) in depth in the course of half an hour; these phenomena are said to be caused by variances in atmospheric pressure on different parts of the surface of the water.