The area forms a geographical entity around the mouth of the Lérez River in the South West of Galicia, which flows into the Atlantic Ocean at the city of Pontevedra, where it creates Pontevedra's ria, having 6 municipalities. The boundaries are characterised by natural landmarks: The Lanzada isthmus in the North, the Cabo Udra in the South, the islands Ons and Onza in the West.