The Agogna is a left tributary of the Po, and about 140 km long. It flows through the two Italian regions of Piedmont and Lombardy. Its source is located between Lake Orta and Lake Maggiore on Mottarone. Then, his course leads south through the provinces of Novara and Pavia. In Balossa Bigli, in the municipality of Mezzana Bigli he finally empties into the Po.
During the Napoleonic Wars, there was a department that was named after the river and its capital was Novara.