The Valdavia River is a Spanish river that rises in the foothills of the Sierra del Brezo (Monastery of San Roman) in Santibáñez de la Peña; it passes through the valle de la Valdavia, to which it gives its name, through villages such as Congosto de Valdavia, Buenavista de Valdavia, Villaeles de Valdavia and Castrillo de Villavega; receives the waters of the Río Boedo in Osorno; and enters the Burgos province to flow into the Pisuerga next to Melgar de Fernamental.