O Porto do Son is a municipality located in the province of A Coruña within the autonomous community of Galicia, Spain. It is situated in the comarca of Noia and covers an area of approximately 25 km by 6 km.
The municipality encompasses a collection of coastal towns and villages, including the town of O Porto do Son and Portosín. The region is characterized by its numerous beaches and historical landmarks, most notably the "Castro de Baroña," which are recognized as famous Celtic ruins.