The highest mountains in the valley are the Weissmies (4,017 m), the Lagginhorn (4,010 m) and the Fletschhorn (3,993 m), all in the Pennine Alps. On the other side (Lepontine Alps), the highest summit is Monte Leone (3,553 m). The most important pass in the valley is the Simplon, connecting Brig to Domodossola.