Saint-Denis, city in Réunion (an overseas department of France), capital of the department, on the northern coast of the island of Réunion, at the mouth of the Saint-Denis River, in the Indian Ocean. It is Réunion's largest city and the department's main administrative, commercial, and communications center. The University Center of Réunion (1950); the Léon-Dierx Museum, which houses collections of historic items and fine art; and the Natural History Museum are here. The community was established by the French in the late 17th century and grew as a stop on trade routes between Europe and Asia. Population (1990) 121,952.