One of the four great rivers of France, rises on Mount St. Gothard, in the Swiss Alps; passes through the Lake of Geneva, and flowing in a south-westerly course to Lyons, is there joined by its chief affluent, the Saône, hence it flows due S.; at Arles it divides into two streams, which form a rich delta before entering the Gulf of Lyons, in the Mediterranean; length, 504 m.; navigable to Lyons, but the rapid current and shifting sandbanks greatly impede traffic.