SEINE (anc. Sequana), a river of France, rises in the department of Cote d'Or, in the heights of Langres, which separate it from the valley of the Saône. The general direction of its course throughout is towards the N.W.; but it has many curves and windings. It traverses the departments of Aube, Seine-et-Marne, Seine-et-Oise, Eure,
and Seine-Inférieure; and falls into the English Channel by a wide estuary, south of Havre. Its whole length is 470 miles, though the distance in a straight line from its source to its mouth is only 270. The river is navigable for large vessels up to Rouen, and for boats as far as Méry, below Troyes, 380 miles from its mouth; but by means of a canal, vessels may ascend as far as Troyes. There are falls at Nogent-sur-Seine; but these are surmounted by locks. The waters of the Seine are connected by means of canals with those of the Rhone, the Loire, and the Scheldt. The chief affluents of the rivers are, from the right, the Aube, the Marne, with its tributary the Ourcq, the Oise, and the Epte; and from the left the Yonne, Loing, Eure, and Rille. It flows through a rich and beautiful region of hill and dale, studded with many splendid mansions, picturesque villages, and busy towns. The principal of the latter that stand on its margin are Chatillon, Bar-sur-Seine, Troyes, Nogent-sur-Seine, Melun, Paris, Mantes, Rouen, and Havre. None of the rivers of France are more abundantly stocked with fish. The elevation of the Seine at its source is 1426 feet above the sea, and the greater part of its fall takes place in the upper part of its course; for at Troyes it is only 330 feet above the sea. Its width at Paris is from 300 to 500 feet, and at its mouth about 7 miles. Owing to the comparatively small incline of its course, the Seine flows with a smooth gentle current, and is not subject to violent inundations. Its estuary is somewhat encumbered with shifting sand-banks; and like that of some other rivers, is exposed every tide to a huge perpendicular wave from the sea, called the barra or bore. In a commercial point of view the Seine is most important, as it greatly facilitates the supply of the capital both with articles of rural produce from the country in the upper part of its course, and with foreign merchandise from its mouth.