The Ource is a 100 km (62 mi) long river in northeastern France, right tributary of the river Seine. Its source is in the Haute-Marne département, 2 km south of Poinson-lès-Grancey. It flows generally northwest. It joins the Seine at Bar-sur-Seine.Its course crosses the following départements and communes:Haute-Marne: Poinson-lès-GranceyCôte-d'Or: Recey-sur-Ource, Brion-sur-Ource, Autricourt, Grancey-sur-OurceAube: Essoyes, Celles-sur-Ource, Bar-sur-Seine