The Tagus flows through Lisbon before entering the Atlantic Ocean. Known as the Tejo in Portuguese and the Tajo in Spanish, it is the longest river on the Iberian Peninsula.
The river rises in Spain’s Montes Universales and travels generally westward across Spain and Portugal. At Lisbon, it widens into the Tagus Estuary, a large tidal water body that opens to the Atlantic and has long supported shipping, fishing and port activity.
Lisbon developed on the northern bank of this estuary, while the river’s broad waterfront has influenced the city’s trade, architecture and maritime history. Portuguese explorers departed from the Tagus during the country’s Age of Discoveries.
The Douro and Guadiana are also important Iberian rivers, but they do not pass through Lisbon. The Ebro flows to the Mediterranean, while the Tagus is the river associated with Lisbon’s Atlantic-facing estuary.