Cergnago is a comune, or municipality, located in the Province of Pavia within the Lombardy region of northern Italy. It is situated approximately 45 kilometers (28 miles) southwest of Milan and about 30 kilometers (19 miles) west of the city of Pavia.
As of January 1, 2018, the municipality covered an area of 13.6 square kilometers (5.3 square miles) with a recorded population of 719 residents.