Castel Maggiore is an Italian commune situated in the Metropolitan City of Bologna within the Emilia-Romagna region of northern Italy. It is located approximately 9 kilometres (6 miles) north of the city center of Bologna.
Despite its name, which translates to "Great Castle," the municipality's designation originates from the earlier name Castaniolo Maggiore. This historical name means "Bigger Chestnut Tree," a reference to the nearby village of Castagnolino, which translates to "Small Chestnut Tree."