Baton Rouge is the capital city of the U.S. state of Louisiana. Located on the western bank of the Mississippi River, it had a population of 227,…Baton Rouge is the capital city of the U.S. state of Louisiana. Located on the western bank of the Mississippi River, it had a population of 227,470 as of 2020; it is the seat of Louisiana's most populous parish, East Baton Rouge Parish, and the center of Louisiana's second-largest metropolitan area and city, Greater Baton Rouge.