Opelousas (French: Les Opélousas; Spanish: Los Opeluzás) is a small city, and the parish seat of, St. Landry Parish, Louisiana, United States. Interstate 49 and U.S. Route 190 were constructed with a junction here. According to the 2020 census, Opelousas has a population of 15,786, and is currently declining at a rate of -1.16% annually and its population has decreased by -6.53% since the most recent census, which recorded a population of 16,634 in 2010. Opelousas is the principal city for the Opelousas-Eunice Micropolitan Statistical Area, which had an estimated population of 80,808 in 2020. Opelousas is also the fourth largest city in the Lafayette-Acadiana Combined Statistical Area, which has a population of 537,947.