The Epte is a river in Seine-Maritime and Eure, in Normandy, France. It is a right tributary of the Seine, 112.5 km (69.9 mi) long. The river rises in Seine-Maritime in the Pays de Bray, near Forges-les-Eaux, and empties into the Seine not far from Giverny. One of its tributaries is the Aubette de Magny. In 911, the Treaty of Saint-Clair-sur-Epte established the river as the historical boundary of Normandy and Île-de-France.