Its source is on Cornone di Blumone, a peak in the Rhaetian Alps, near the Passo del Termine within the commune of Breno, in the Parco regionale dell'Adamello regional park. The river then runs through the Val di Caffaro entering the territory of Bagolino and flows into the Chiese just before the latter enters lago d'Idro at Ponte Caffaro.