Louisiana Revised Statutes 50:1 – Adoption; parishes comprising north and south zones
A. The systems of plane coordinates which have been established by the National Ocean Service/National Geodetic Service, formerly the United States Coast and Geodetic Survey, or its successors for defining and stating the geographic positions or locations of points on the surface of the earth within the state of Louisiana are hereafter to be known and designated as the Louisiana Coordinate System of 1927 and the Louisiana Coordinate System of 1983.
B. For the purpose of the use of these systems, the state is divided into a North Zone, South Zone, and an Offshore Zone.
C. The area now included in the following parishes shall constitute the North Zone: Avoyelles, Bienville, Bossier, Caddo, Caldwell, Catahoula, Claiborne, Concordia, DeSoto, East Carroll, Franklin, Grant, Jackson, LaSalle, Lincoln, Madison, Morehouse, Natchitoches, Ouachita, Rapides, Red River, Richland, Sabine, Tensas, Union, Vernon, Webster, West Carroll, and Winn.
D. The area now included in the following parishes shall constitute the South Zone: Acadia, Allen, Ascension, Assumption, Beauregard, Calcasieu, Cameron, East Baton Rouge, East Feliciana, Evangeline, Iberia, Iberville, Jefferson, Jefferson Davis, Lafayette, Lafourche, Livingston, Orleans, Plaquemine, Pointe Coupee, St. Bernard, St. Charles, St. Helena, St. James, St. John the Baptist, St. Landry, St. Martin, St. Mary, St. Tammany, Tangipahoa, Terrebonne, Vermilion, Washington, West Baton Rouge, and West Feliciana.
E. The area now included in that area of the Gulf of Mexico defined as being within 200 miles of the state of Louisiana shall constitute the Offshore Zone.
Acts 1985, No. 913, §1.