Réunion, overseas department and administrative region of France, largest of the Mascarene island group in the Indian Ocean, southeast of Madagascar. The island is volcanic in origin and is mountainous. The highest peak, Piton des Neiges, rises 3,069 m (10,069 ft) above sea level. The climate is tropical, with a rainy season lasting from November to April; the island is subject to destructive tropical storms. The island's economy is controlled by the cultivation of sugarcane. The principal exports are sugar, lobsters, rum, vanilla, and perfume essences. The capital of Réunion is Saint-Denis, a port on the northern coast. The island is densely populated. The inhabitants are mainly of mixed African, Asian, and French descent, and about 90 % are Roman Catholic.