Guadiana

The Guadiana River , or Odiana, is an international river defining a long stretch of the Portugal-Spain border, separating Extremadura and Andalusia from Alentejo and Algarve . The river's basin extends from the eastern portion of Extremadura to the southern provinces of the Algarve; the river and its tributaries flow from east to west, then south through Portugal to the border towns of Vila Real de Santo António and Ayamonte , where it flows into the Gulf of Cádiz. With a course that covers a distance of 829 kilometres , it is the fourth-longest in the Iberian peninsula, and its hydrological basin extends over an area of approximately 68,000 square kilometres .

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