The Yonne is a river in France, left tributary of the Seine. It is 292 km long. The river gives its name to the Yonne département. Its source is in the Nièvre département, in the Morvan hills near Château-Chinon. It flows into the river Seine in Montereau-Fault-Yonne.
The Yonne flows through the following départements and towns:
- Nièvre: Château-Chinon, Clamecy
- Yonne: Auxerre, Migennes, Joigny, Villeneuve-sur-Yonne, Sens
- Seine-et-Marne: Montereau-Fault-Yonne