PORT LOUIS, a fortified sea-port of France, in the department of Morbihan, and arrondissement of L'Orient. It is situated at the mouth of the river Blavet, on the bay of its own name, and is inclosed by the sea on three sides. It has a citadel of great strength, three churches, a naval hospital and exchange, 365 houses, and 3480 inhabitants. Lat. 47. 45. Long. 3. 32. W.