The Ognon (French pronunciation: [ɔɲɔ̃] ) is a river of Eastern France. It is a left tributary of the Saône, which it joins in Pontailler-sur-Saône. Its source is in Haut-du-Them-Château-Lambert in the Vosges Mountains near the Ballon d'Alsace. Its length is 214 km (133 mi) and its basin area is 2,308 km (891 sq mi).

The Ognon flows through the following departments and towns: Haute-Saône, with Mélisey, Lure, Villersexel, Pesmes; Doubs, with Rougemont; Jura; Côte-d'Or, with Pontailler-sur-Saône.

Some of its tributaries include:

• The Rahin
• The Scey
• The Reigne
• The Buthiers

• Website of an association of owners of historical sites in the Ognon valley (french - english)