Baton Rouge is the capital city of the U.S. state of Louisiana. Located on the eastern 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 …Baton Rouge is the capital city of the U.S. state of Louisiana. Located on the eastern 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, Greater Baton Rouge.