Yonne is a river in France, tributary of the Seine. It is about 293 km long. The river gives its name to the Yonnedépartement. Its source is in the Nièvre département, in the Morvan hills near Château-Chinon. It flows through the départements Nièvre, Yonne and Seine-et-Marne. It flows into the river Seine in Montereau-Fault-Yonne. Cities along the river include Clamecy, Auxerre and Sens.
YONNE, a department of central France, formed partly from the province of Champagne proper (with its dependencies, Senonais and Tonnerrois), partly from Burgundy proper (with its dependencies, the county of Auxerre and Avallonnais) and partly from Gatinais (Orleanais and Ile-deFrance).
To the W. of the Yonne, in the Puisaye, are the sources of the Loing, another tributary of the Seine, and of its affluents, the Ouanne and the Lunain.
The Yonne is navigable throughout the department, and is connected with the Loire by the canal of Nivernais, which in turn is connected with that of Briare, which connects the Seine and the Loire.