The Archdiocese of New Orleans is a Latin Church ecclesiastical division of the Catholic Church spanning Jefferson, Orleans, Plaquemines, St. Bernard, St. Charles, St. John the Baptist, St. Tammany, and Washington civil parishes of southeastern Louisiana. It is the second to the Archdiocese of Baltimore in age among the present dioceses in the United States, having been elevated to the rank of diocese on April 25, 1793, during Spanish colonial rule.

Jefferson Parish is a parish in the U.S. state of Louisiana. As of the 2020 census, the population was 440,781. Its parish seat is Gretna, its largest community is Metairie, and its largest incorporated city is Kenner. Jefferson Parish is included in the Greater New Orleans area.