Born in the highlands of Valdeburón, northwest of Riaño, and passes through the province of León and Palencia capital. It crosses the Duero river, already in Valladolid, by the end of Tudela de Duero, where it takes direction to Coca and Villacastín, in Segovia. After crossing Ávila, the gorge takes a course through Madrid towards the vicinity of Llerena, where it dies.