Port Louis, city (1996 est. pop. 135,371), capital of Mauritius, NW Mauritius, a port on the Indian Ocean. It is the nation's largest city and its economic and administrative center. Its economy is dominated by its well-sheltered port, which handles Mauritius's international trade; there are extensive facilities for processing and storing sugar, the main export. Port Louis is connected with the interior of the country by railroads and roads and has an international airport. Manufacturing is dominated by garments and textiles, but also includes chemicals, plastics, and pharmaceuticals. Tourism is important, as are high-tech services. Port Louis was founded in 1735 by Bertrand François Mahé de La Bourdonnais, governor of the French colony on Mauritius (then called Île de France). The population of Port Louis is now largely made up of the descendants of laborers who immigrated from India in the 19th cent. The hill-top Citadel (1838) dominates the city, which is laid out in a rectangular pattern. The Mauritius Institute (1880), which studies the island's flora and fauna and operates a natural history and an art museum, is in Port Louis.