Spanish Río Tajo Portuguese Rio Tejo
Longest waterway of the Iberian Peninsula .
It rises in eastern central Spain and flows west across Spain and Portugal for 626 mi (1,007 km) to empty into the Atlantic Ocean near Lisbon . It covers the heart of the two nations, and is of vital economic importance. Dams harness it for irrigation and hydroelectric power, and large artificial lakes have been created. Navigable for about 100 mi (160 km) in its lower courses, it supplies a fine natural harbor at Lisbon.