From the boundary of the administrative regions of Abitibi-Témiscamingue and Nord-du-Québec, the upper part of the river, Barry Lake (Saint-Cyr River South) to Canusio Lake (elevation of 392 meters ), rather to the hydrographic slope of the Nottaway River, via the Mégiscane River which was harnessed by Hydro-Quebec to the emissary of “Lac du Poète”.