It is named after the East Patapedia River that forms the territory's western boundary. This river is the main outlet of Lake Supérieur and a tributary of the Patapédia River.
^ ab"Rivière-Patapédia-Est". Répertoire des municipalités (in French). Ministère des Affaires municipales, des Régions et de l'Occupation du territoire. Retrieved 2012-02-06.