Length: 1,007 kilometers (625 miles)
Also known as the Tagus, the Tajo is longest Spanish river, which starts in the mountains east of Madrid. It drains the central part of the Iberian Peninsula. From the mountains, it goes past Teruel, through central Spain, past Toledo, and then forms part of the Spanish-Portuguese border. This river then continues into Portugal and drains into the Atlantic Ocean at Lisbon. The lower and upper courses of this river are go through some deep gorges, and also get broken up by waterfalls. The Tajo’s water is a source of power in Spain, as many dams and reservoirs are built on its premises to make hydroelectricity. Its major tributaries are the Alagon and Jarama rivers.
Length: 910 kilometers (565 miles)
The River Ebro is the most voluminous in Spain, starting in Fontibre. From there, it flows through the cities of Miranda de Ebro, Logrono, Zaragoza, and then through Catalonia, through Flix, Tortosa and Amposta. It terminates in the Mediterranean Sea at Tarragona. This is a significant river in history, having been the point of division from the northern Roman area and the southern Carthaginian area. The Ebro Delta also exists in Tarragona, and is a huge wetland area that is used to cultivate rice, citrus and vegetables. The Ebro has the greatest discharge of any river in Spain.
Length: 895 kilometers (556 miles)
Also known as the Douro, this river flows throughout the Iberian peninsula, starting in Sorio in north-central Spain and Portugal. From there, it flows through the Northern Meseta and then through Almazan, continuing through Aranda de Duero, Tordesillas, Zamora. It then goes through some canyons over in Portugal, before it empties out into the Atlantic Ocean. The Ribera Del Duero region in Spain for red wine, especially for the Tinto Fino type. In Spain, the watershed of the Duero covers around 16% of the whole country.
Length: 657 kilometers (408 miles)
The Guadiana River flows through south-central Spain, as well as south-eastern Portugal; it also forms part of the border between these countries. It begins in Spain in the mountains of the Cuenca province, then flowing to form marshy areas around Damiel. As it goes westward, it cuts through gorges in the Toledo Mountains. Some of this area has utilized the river’s water to generate hydroelectric power. This river has about 30 major tributaries as well.