Frías is a town located in the northern part of the province of Burgos, in Castile and León, Spain. In 2010 it had a population of only 275 inhabitants. Frías is a historic medieval town on a hill above the river Ebro, which has been a strategic point to cross river Ebro in the routes communicating with the Cantabrian Sea. Today the town is a popular tourist spot. It has an impressive castle dominating the river and the twelfth-century bridge across it.