What is "azergues"

The Azergues is a river in the Rhône department, in eastern France. It is a right tributary of the Saône, which it joins in Anse. Its source is in the Beaujolais hills, near Chénelette. The Azergues flows through the following towns: Lamure-sur-Azergues, Le Bois-d'Oingt, Chessy, Châtillon, Chazay-d'Azergues and Anse.