The Tagus (/ˈteɪɡəs/ TAY-gəs; Spanish: Tajo [ˈtaxo]; Portuguese: Tejo [ˈtɛʒu]; see ) is the longest river in the Iberian Peninsula. The river rises in the Montes Universales near Teruel, in mid-eastern Spain, flows 1,007 km (626 mi), generally west with two main south-westward sections, to empty into the Atlantic Ocean in Lisbon. Its drainage basin covers 80,100 km2 (30,927 sq mi) – exceeded in the peninsula only by the Douro. The river is highly used. Several dams and diversions supply drinking water to key population centres of central Spain and Portugal; dozens of hydroelectric stations create power. Between dams it follows a very constricted course, but after Almourol, Portugal it has a wide alluvial valley, prone to flooding. Its mouth is a large estuary culminating at the major port,