The Château de Chaumont (or Château de Chaumont-sur-Loire) is a castle in Chaumont-sur-Loire, Loir-et-Cher, France. The castle was founded in the 10th century by Odo I, Count of Blois. It is located on top of a hill overlooking the Loire River. It was built to protect the borders between Blois and Anjou.