The Orge (French pronunciation: [ɔʁʒ] ) is a 54.1-kilometre (33.6 mi) long river in France, left tributary of the Seine. Its source is in the village Saint-Martin-de-Bréthencourt. Its course crosses the départements of Yvelines and Essonne. It flows northwest through the towns of Dourdan, Saint-Chéron, Breuillet, Arpajon, Savigny-sur-Orge, and Viry-Châtillon, finally flowing into the Seine in Athis-Mons, south of Paris. The towns located on the banks of the river usually have s/ Orge added to their name (i.e. Épinay-sur-Orge, Longpont-sur-Orge, Villiers-sur-Orge). The Yvette is a tributary of the Orge.
