Tagus (Latin Tagus, Spanish Tajo, Portuguese Tejo) is the largest river on the Iberian Peninsula. It measures 1,008 kilometers in length, 910km of which are in Spain, the rest in Portugal.
The source of the Tagus is the Fuente de García, in the Albarracín mountains. It ends in the Atlantic Ocean by Lisbon.
Its delta is partially inverted, and forms a large lagoon.