ORNE, a river of France, giving its name to the above department, in which it rises, not far from Séez. It flows northwards to the borders of the department of Calvados, then turns N. by E., and falls into the English Channel, after a course of 90 miles. It receives the Noireau, the Aize, and the Oden, and is navigable as far as Caen, 10 miles from its mouth.