city, seat (1805) of St. Landry parish, south-central Louisiana, U.S. It lies on the Gulf Coastal Plain, 20 miles (32 km) north of Lafayette. Founded in 1720 as a French garrison and trading post and named for the Opelousas Indians, it became a sanctuary for Acadians (Acadia) exiled from Nova Scotia. The site of the State Supreme Court until 1898, it was incorporated as a town in 1821 and was the temporary Confederate capital of Louisiana during the American Civil War.

Its economy depends largely on cotton and cattle, though it has been augmented by the area's petroleum and natural gas reserves (discovered in 1927 at nearby Port Barre). The city is associated with sweet potatoes and holds a “Yambilee” (yam festival) each October. Opelousas is also the birthplace of zydeco-music pioneer Clifton Chenier. Its Jim Bowie Museum displays Bowie mementos and French and Acadian relics. Nearby, on Lake Chicat, is the Louisiana State Arboretum, containing various plant species endemic to Louisiana. Inc. city, 1898. Pop. (1990) 18,151; (2000) 22,860.