Pero is a comune in the Province of Milan in the Italian region Lombardy, located about 9 kilometres northwest of Milan. As of 31 December 2004, it had a population of 10,378 and an area of 5.0 square kilometres. The municipality of Pero contains the frazioni Cerchiate and Cerchiarello. Pero borders the following municipalities: Rho, Milan. Pero is linked to Milan and Rho by the underground line M1.