BOUILLON, a town of the Netherlands, in the duchy of the same name, and in the county of Luxemburg, with a fortified castle, which is seated on a rock that is almost inaccessible. The French took it in 1676; upon which it was given to the duke of Bouillon. This duchy was a sovereignty, independent of France; and in 1792, the king of Great Britain granted to Philip d'Auvergne, captain in the royal navy, his license to accept the succession to the said duchy, in the case of the death of the hereditary prince, only son of the reigning duke, without issue male, pursuant to a declaration of his serene highness, in 1791, "at the desire, and with the express and formal consent of the nation." Accordingly, Captain d'Auvergne afterwards assumed the title of prince of Bouillon. In May 1794 this town was taken by storm, by General Beaulieu, after defeating a considerable body of republicans, and given up to pillage; 1200 French were killed, and 300 taken prisoners. It is seated near the river Semois, 12 miles north of Sedan. E. Long. 5. 20. N. Lat. 49. 45.