Valle Mosso was a comune located in the Province of Biella within the Piedmont region of Italy. It was situated approximately 75 kilometres northeast of Turin, 85 kilometres northwest of Milan, and 9 kilometres northeast of Biella.
Until December 31, 2018, Valle Mosso functioned as an autonomous municipality. During this period, it shared borders with the municipalities of Bioglio, Campiglia Cervo, Mosso, Pettinengo, Strona, Trivero, Vallanzengo, Valle San Nicolao, and Veglio.