Opelousas (French: Les Opelousas) is a small city in and the parish seat of St. Landry Parish, Louisiana, United States. Interstate 49 and U.S. Route 190 were constructed with a junction here. The population was 22,860 at the 2000 census. In 2004 the city annexed territory and population expected to give it more than 25,000 people in total. In the 2010 census, the population was 16,634. Opelousas is the principal city for the Opelousas-Eunice Micropolitan Statistical Area, which had an estimated population of 92,178 in 2008. Opelousas is also the third-largest city in the Lafayette-Acadiana Combined Statistical Area, which has a population of 537,947.