The municipality of Osor comprises the urban area and the neighbourhoods of Mines d’Osor, El Coll, Sant Miquel de Maifré and Santa Creu d’Horta. It has an abrupt orography: the valley is surrounded by the following mountains: Porta Barrada, Sant Benet, El Coll and Sant Gregori and by the Solterra massif, surrounded by the highest peaks in Les Guilleries: Sant Gregori, Sant Benet and Sant Miquel de les Formigues.