French river rising on the Langres plateau in the département of Côte d'Or, 30 km/19 mi northwest of Dijon, and flowing 774 km/472 mi northwest through Paris and Rouen to join the English Channel at Le Havre. It is the third-longest, but economically the most important, river in the country.
Course After rising it flows through Champagne, past Troyes, and turns west and then south, past Nogent-sur-Seine, the Forest of Fontainebleau, and Melun, before arriving at Paris. It describes several large loops while flowing through the Ile-de-France, and continues, still in a generally northwesterly direction, past Elbeuf and Rouen, through Normandy to its estuary south of Cap de la Hève. Throughout the lower half of its course the river meanders considerably.
River use The Seine has numerous tributaries, which flow to it from the raised edges of the vast Paris basin. Among them are the Yonne, Aube, Marne, and Oise. Together the Seine and its tributaries carry more than half of the inland water traffic of France. The Seine rivers and canals are also linked with the Meuse, Escaut (Schelde), and Somme, with the waterways of Belgium, with the Sâone (and hence with the Rhône and the Mediterranean), with the Loire, and with the Rhine and the German waterways. Sea-going vessels use the Seine as far as Rouen, and barges travel as far as St-Mesnin (and then by canal to Bar); small sea-going vessels can travel as far as Paris. The cities of Paris, Rouen, and Le Havre owe much of their economic growth and prosperity to the Seine which carries the bulk of France's commercial water-way traffic. The lower reaches of the river require frequent dredging, and there is a strong bore, or tidal wave. The banks are dyked as far as Rouen.