Saint-Denis (French pronunciation: ​[sɛ̃.də.ni], or unofficially Saint-Denis de la Réunion for disambiguation) is the préfecture (administrative capital) of the French overseas region and department of Réunion, in the Indian Ocean. It is located at the island's northernmost point, close to the mouth of the Rivière Saint-Denis.Saint-Denis is the most populous commune in the French overseas departments.