Lake Geneva

The area is 581 km², of which 347 km² is in Switzerland, and the rest in France. The northern shore and eastern corner are in the Swiss canton of Vaud, the southern shore is in the French département of Haute-Savoie, and the canton of Geneva curls around the western corner. A small finger of the canton of Valais touches the south-eastern shore.

It is fed by the River Rhône, entering in the east, and exiting at Geneva. It is 72 km long, with a width averaging 8 km reaching a maximum of 14 km. The part near Geneva is called Petit Lac, separated by a narrowing from the main Grand Lac. To the north it rises to the Jura Mountains, and to the south to the Savoy and Valais Alps. Its greatest depth is 310 m and the average is 80 m. The waters are renowned as exceptionally blue.

Known to the Romans as Lacus Lemanus, it is called Lac de Genève in French and Genfersee in German, but in the eighteenth century the classical name was restored, and Lac Léman is now the usual French name.

Its beauty made it a popular resort for people of all nationalities, especially the English. It was while staying there that Mary Shelley conceived the novel Frankenstein, and Lord Byron wrote his poem on the prisoner of Chillon, a castle near Montreux. Before the Napoleonic period, the Republic of Geneva was an independent state much more tolerant than France, so Voltaire lived here at Ferney.

The phenomenon of the seiche was first described with reference to Lake Geneva, which has these oscillations of the whole body of water, resembling tides, caused by variations in wind and pressure setting up standing waves that resonate down the long lake. Here they last several minutes, sometimes up to an hour, and may expose large parts of lakebed that are normally underwater.