Ascension Parish is a parish located in the U.S. state of Louisiana. As of the 2020 census, the population was 126,500. Its parish seat is Donaldsonville. The parish was created in 1807. Ascension Parish is part of the Baton Rouge metropolitan statistical area. Ascension Parish is one of the 22 parishes that make up Acadiana, the heartland of the Cajun people and their culture.