St. Bernard Parish is a parish in the U.S. state of Louisiana. The parish seat and largest community is Chalmette. The parish was formed in 1807. St. Bernard Parish is part of the New Orleans–Metairie metropolitan statistical area; the parish is located southeast of the city of New Orleans and comprises the Chandeleur Islands and Chandeleur Sound in the east. St. Bernard was the fastest growing parish in Louisiana from 2010 to 2020, increasing from a population of 35,897 in the 2010 census to 43,764 in 2020.