Castelnaudary is a commune in the Aude department in the Languedoc-Roussillon region in south France. It is in the former province of the Lauragais and famous for cassoulet of which it claims to be the world capital, and of which it is a major producer. Castelnaudary is also a market town, and the capital of the territory of Lauragais. It is the main port of the Canal du Midi to which it owed a period of prosperity in the 17th century when agricultural and manufactured produce became easier to export. The Grand Bassin in the town is at 7 ha the largest open area of water in the canal, and is today its major pleasure port.