East Baton Rouge Parish is the most populous parish in the U.S. state of Louisiana. Its population was 456,781 at the 2020 census. The parish seat is Baton Rouge, Louisiana's state capital. East Baton Rouge Parish is located within the Greater Baton Rouge area.

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 (county-equivalent), East Baton Rouge Parish, and the center of Louisiana's second-largest metropolitan area and city, Greater Baton Rouge.