Lafayette is a city in and the parish seat of Lafayette Parish, Louisiana, located along the Vermilion River in the southwestern part of the state. The city of Lafayette is the fourth-largest in the state, with a population of 126,143 according to 2018 U.S. Census estimates. It is the principal city of the Lafayette, Louisiana Metropolitan Statistical Area, with a 2015 estimated population of 490,488. The larger trade area or Combined Statistical Area of Lafayette-Opelousas-Morgan City CSA was 627,146 in 2015. Its nickname is The Hub City.