Châteaugiron is a commune in the Ille-et-Vilaine department of Brittany in northwestern France. It extended on 1st January 2017 by merging with the former communes of Saint-Aubin-du-Pavail and Ossé.PopulationInhabitants of Châteaugiron are called Castelgironnais in French.Sister cities Puszczykowo, Poland