Valois, historic region, now comprised in Aisne and Oise depts., N France. Crépy-en-Valois was its historic capital. It is a rich agricultural area. A county and later a duchy, Valois was the appanage of the royal house of Valois, which succeeded the elder Capetian line (see Capetians) on the French throne. It was incorporated into the royal domain in 1515.