Tagus Basin

The Tagus Basin is the drainage basin of the Tagus River, which crosses the western Iberian Peninsula and empties into the Atlantic Ocean at Lisbon. Covering 78,467 square kilometers, it is the third-largest river basin on the peninsula after the Douro and Ebro, with 66 percent of its area in Spain and 34 percent in Portugal. The basin runs in an elongated east-west band, rising in the Sierra de Albarracín in Spain and wedged between the Central System to the north, the Montes de Toledo and Sierra de Montánchez to the south, and the Iberian System to the east. Structurally it is a graben filled with Cenozoic sands, clays, marls, gypsum and limestone, and it is home to roughly 10 million people. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/