|Country||Spain and Portugal|
The Duero is a river on the Iberian Peninsula, in Spain and Portugal. Its Portuguese name is Douro. It is 897 kilometres (557 mi) long, and flows into the Atlantic Ocean near Porto. It rises in Soria Province, in Spain. The river marks the border between Spain and Portugal for 112 kilometres (70 mi). 213 kilometres (132 mi) of the lower course is in Portugal. The Douro railway line runs along the river, in Portugal. The region is also known for wine-making and tourism.