As “Elvo Valley” I mean not only the upper part, in the mountains, where in the form of a stream the Elvo flows impetuously, but also the countryside further down. Between Mongrando, Occhieppo and Borriana, in fact we always find the Elvo, now a river, which flows slower in its wide sandy bed. The Elvo rises at an altitude of 2,300 m, on Mount Mars, and descending collects the waters of Viona, Ingagna, Oremo and Olobbia, near Mongrando and Borriana; in Vercellese, then, it flows into the Cervo and Sesia, after a course of almost 60 km.