The Staffora is a river of the Oltrepò Pavese in the

Province of Pavia The province of Pavia ( it, Provincia di Pavia) is a province in the region of Lombardy in northern Italy; its capital is Pavia. , the province has a population of 548,722 inhabitants and an area of ; the town of Pavia has a population of 72,205 ...

, north-west

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...

and a right-side tributary of the Po. It is probably the river known to the Romans as the Iria.

Course

The river rises in the Ligurian

Apennines The Apennines or Apennine Mountains (; grc-gre, links=no, Ἀπέννινα ὄρη or Ἀπέννινον ὄρος; la, Appenninus or – a singular with plural meaning;''Apenninus'' (Greek or ) has the form of an adjective, which wou ...

at the Fontana di S. Giacomo, elevation , near the Passo del Giovà, which lies just to the east of the peak of Monte Chiappo in the commune of Santa Margherita di Staffora. It flows at first through a deep and narrow valley, receiving from the right the waters of the torrents Montagnola and Aronchio before reaching

Varzi Varzi is a '' comune'' (municipality) in the Province of Pavia in the Italian region Lombardy, located about 70 km south of Milan and about 40 km south of Pavia. Varzi borders the following municipalities: Bagnaria Bagnaria ( Lomba ...

where the valley begins to widen. The torrent Crenna enters from the right and the Lella from the left before the Staffora receives its major affluents: from the right: the torrent Nizza at

Ponte Nizza Ponte Nizza is a '' comune'' (municipality) in the Province of Pavia in the Italian region Lombardy, located about 70 km south of Milan and about 35 km south of Pavia. Ponte Nizza borders the following municipalities: Bagnaria, Cecim ...

and the torrent Ardivestra at Godiasco and from the left the torrent Semola near Ponte Nizza. The river flows through Salice Terme (administratively a

frazione A ''frazione'' (plural: ) is a type of subdivision of a ''comune'' (municipality) in Italy, often a small village or hamlet outside the main town. Most ''frazioni'' were created during the Fascist era (1922–1943) as a way to consolidate territ ...

of Godiasco) before entering the Pianura Padana at Rivanazzano Terme. The Staffora then passes through the eastern outskirts of

Voghera The Castle of Voghera in a 19th-century etching. Voghera ( Vogherese dialect of Emilian: ''Vughera''; Latin: ''Forum Iulii Iriensium'') is a town and ''comune'' in the Province of Pavia in the Italian region Lombardy. The population was 39,3 ...

, the principal town on its course, before entering the Po near

Cervesina Cervesina is a ''comune'' (municipality) in the Province of Pavia in the Italian region Lombardy, located about south of Milan and about southwest of Pavia. As of 31 December 2004, it had a population of 1,186 and an area of .All demographics and ...

Regime

Although the river flows throughout the year, fed by perennial springs as well as by seasonal rains and melting ice, the regime is torrential: its discharge can vary between