French Lac Léman German Genfersee
Lake, on the border of southwestern Switzerland and southeastern France.
About 134 sq mi (347 sq km) of the lake's area is Swiss and 90 sq mi (234 sq km) French. Lying at an elevation of 1,220 ft (372 m), it is 45 mi (72 km) long with an average width of 5 mi (8 km). It is formed by the Rhône River , which enters at the eastern end and leaves at the western end through the city of Geneva . The water level is subject to fluctuations known as seiches, in which the lake's water mass rhythmically swings from shore to shore.