Bosco Marengo ( in the local dialect ir Bosch) is a municipality with 2509 (as of 31 December 2012) a population of Alessandria in the Italian province (AL ), Region Piedmont.
Still belongs to the municipality of the district of Donna. Neighboring municipalities are Alessandria, Basaluzzo, Casal Cermelli, Fresonara, Frugarolo, Novi Ligure, Pozzolo Formigaro, Predosa and Tortona. The patron saint of the place is San Pio V.
The village lies at an altitude of 121 m above sea level. The municipality covers an area of 44.7 km ².