On the northern slopes of Monte Viso are the headwaters of the Po, the longest Italian river, the so-called Pian del Re (2,020 m). The Monviso group is surrounded by the Valle Po, Valle Varaita and, on the French side, the Guil valley. The northern sector of the group, from the Punta Gastaldi to the Col de la Traversette, is located on the French border.