Lake Geneva is a deep lake on the north side of the Alps , shared between Switzerland and France. It is one of the largest lakes in Western Europe and the largest on the course of the Rhône. Sixty percent (345.31 km2 or 133.32 sq mi) of the lake belongs to Switzerland (the cantons of Vaud, Geneva and Valais) and forty percent (234.71 km2 or 90.62 sq mi) to France (the department of Haute-Savoie ).

While the exact origins of the name are unknown, the name Lacus Lemanus was in use during the time of Julius Caesar. Lemannus comes from Ancient Greek Liménos Límnē (Λιμένος Λίμνη) meaning "port's lake". In Medieval Latin it was known as Lacus Lausonius, although this name was also used for a town or district on the lake, or Lacus Losanetes; the equivalent in Old French was