Vidalia is the largest city and the parish seat of Concordia Parish, Louisiana, United States. The population was 4,299 as of the 2010 census. Vidalia is located on the west bank of the Mississippi River. The city of Natchez, Mississippi, lies on the opposite bank of the river, connected by the Natchez–Vidalia Bridge, carrying U.S. Routes 65, 84, and 425.