EPERNON, a town of northern France in the department of Eure-et-Loir, at the confluence of the Drouette and the Guesle, 17 m. N.E. of Chartres by rail. Pop. (1931) 2,03 r . It belonged originally to the counts of Montfort, who, in the 1 1 th century, built a castle here of which the ruins are still left, and granted a charter to the town. In the i3th century it became an inde pendent lordship, which remained attached to the crown of Navarre till, in the i6th century, it was sold by King Henry (afterwards King Henry IV. of France) to Jean Louis de Nogaret, for whom it was raised to the rank of a duchy in 1581. The new duke of Epernon was one of the favourites of Henry III., who were called les Mignons; the king showered favours upon him, giving him the posts of colonel-general in the infantry and of admiral of France. Under the reign of Henry IV. he made himself practically independent in his government of Provence. He died in 1642. After the death of his second son Bernard (166 r) the title of duke of Epernon was borne by the families of Goth and of Pardaillan.