Nervión (Spanish pronunciation: [neɾˈβjon]; Basque: Nerbioi) is a river that runs through the town of Bilbao, Spain into the Cantabrian Sea (Bay of Biscay).

Soon after its source, the river forms a spectacular 300-metre (980 ft) waterfall in the Delika canyon (Alava) and then enters the Biscay province through the city of Orduña.

[3][clarification needed] Since ancient times, the Orduña pass that links Spain's inner plateau with the Nervión valley has had a great economic impact.

Through the centuries, the Nervión valley was a vital communication corridor for Biscay, and the main rail line from Bilbao to the rest of Spain was constructed following the river in 1870.

In 1990 the local authorities launched a plan to overcome this situation, resulting in a constant improvement of the environmental status that after 15 years has transformed the Nervión in to a clean river, full of aquatic life.