Lafayette is the most populous city in and parish seat of Lafayette Parish in the U.S. state of Louisiana, located along the Vermilion River. It is Louisiana's fourth-most populous city with a 2020 census population of 121,374; the consolidated city-parish's population was 241,753 in 2020. The Lafayette metropolitan area was Louisiana's third largest metropolitan statistical area with a population of 478,384 at the 2020 census.