 From Courmayeur these waters flow southwards as the Dora Baltea towards Aosta, eventually joining the Po.However, the extreme western end of the southern side of the massif does lie within France and is bounded by the Vallée des Glaciers (which connects to the Val Veny over the watershed of the col de la Seigne), and its waters flow southwards towards the Isère and onwards to the Rhône.The northeastern end of the massif falls within Switzerland, and is bounded by a separate valley, confusingly also called Val Ferret, and which separates it from the Pennine Alps further east.