Castel Maggiore is an Italian comune with 17,422 inhabitants in the province of Bologna located 9 kilometres north of the centre of Bologna. Literally, its name means Great Castle, but the name is derived from the earlier name Castaniolo Maggiore. Castaniolo is traditionally thought to derive from the Italian for little chestnut. It is not uncommon for tourists to ask for the non-existent "castle" in Castel Maggiore.