Setúbal, Bay of

a bay of the Atlantic Ocean; located off the western coast of the Iberian Peninsula. The Bay of Setúbal is more than 45 km long; depths at the mouth of the bay range from 100 to 200 m. At the end of the bay is a large lagoon, into which the Sado River empties. Tides are semidiurnal and rise to more than 3 m. The port of Setúbal, Portugal, is located at the entrance to the lagoon.