High Alps
It divides the canton of Fribourg into a western French-speaking majority and an eastern German-speaking minority and then follows the eastern boundary of Vaud with the upper Saane/Sarine valley of the Bernese Oberland. Cutting across the High Alps at Les Diablerets, the boundary then separates the French-speaking Lower Valais from the Alemannic-speaking Upper Valais beyond Sierre. It then cuts southwards into the High Alps again, separating the Val d'Anniviers from the Mattertal.