The Guadalquivir is the fifth longest river in the Iberian peninsula and the second longest river with its entire length in Spain. The Guadalquivir is 657 kilometers long and drains an area of about 58,000 square kilometers. It begins at Cañada de las Fuentes (village of Quesada) in the Cazorla mountain range (Jaén), passes through Córdoba and Seville and ends at the fishing village of Bonanza, in Sanlúcar de Barrameda, flowing into the Gulf of Cádiz, in the Atlantic Ocean. The marshy lowlands at the river's end are known as "Las Marismas". It borders Doñana National Park reserve.
The Guadalquivir river is the only great navigable river in Spain. Currently it is navigable to Seville, but in Roman times it was navigable to Córdoba.
The ancient city of Tartessos was said to have been located at the mouth of the Guadalquivir, although its site has not yet been found.