CodeGeo is an online resource for exploring France’s Code Officiel Géographique (COG), the official geographic reference published annually by INSEE. The COG lists administrative areas, including communes, departments, regions, cantons, overseas collectivities, and countries and territories, while documenting changes to their names, codes, boundaries, and status. CodeGeo presents this information in a searchable, navigable format and pairs it with maps based on contours published by IGN, helping visitors explore geographic entities and their relationships.

The site’s 2026 edition, identified as published on 24 February 2026, covers a broad range of administrative units, with figures including 18 regions, 101 departments, and 34,875 communes. It also provides archives and historical records of creations, deletions, mergers, and other changes. Additional reference data covers municipal subdivisions, such as associated and delegated communes and the municipal arrondissements of Paris, Marseille, and Lyon. Available interface languages include French, English, and Japanese. CodeGeo offers a practical way to consult current and historical COG information alongside geographic visualizations.