The Guadiana River ( GWAH-dee-AH-nə, US also gwahd-YAH-nə, Spanish: [ɡwaˈðjana], Portuguese: [ɡwɐdiˈɐnɐ]) is an international river defining a long stretch of the Portugal-Spain border, separating Extremadura and Andalusia (Spain) from Alentejo and Algarve (Portugal). The river's basin extends from la Mancha and 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 (Portugal) and Ayamonte (Spain), where it flows into the Gulf of Cádiz. With a course that covers a distance of 829 kilometres (515 mi), it is the fourth-longest in the Iberian Peninsula, and its hydrological basin extends over an area of approximately 68,000 square kilometres (26,000 mi2) (the majority of which lies within Spain).
