Texas Natural Resources Code - NAT RES § 21.074. Area Within Zones

(a) The area included in the following counties constitutes the North Zone: Armstrong, Briscoe, Carson, Castro, Childress, Collingsworth, Dallam, Deaf Smith, Donley, Gray, Hall, Hansford, Hartley, Hemphill, Hutchinson, Lipscomb, Moore, Ochiltree, Oldham, Parmer, Potter, Randall, Roberts, Sherman, Swisher, and Wheeler.

(b) The area included in the following counties constitutes the North Central Zone: Andrews, Archer, Bailey, Baylor, Borden, Bowie, Callahan, Camp, Cass, Clay, Cochran, Collin, Cooke, Cottle, Crosby, Dallas, Dawson, Delta, Denton, Dickens, Eastland, Ellis, Erath, Fannin, Fisher, Floyd, Foard, Franklin, Gaines, Garza, Grayson, Gregg, Hale, Hardeman, Harrison, Haskell, Henderson, Hill, Hockley, Hood, Hopkins, Howard, Hunt, Jack, Johnson, Jones, Kaufman, Kent, King, Knox, Lamar, Lamb, Lubbock, Lynn, Marion, Martin, Mitchell, Montague, Morris, Motley, Navarro, Nolan, Palo Pinto, Panola, Parker, Rains, Red River, Rockwall, Rusk, Scurry, Shackelford, Smith, Somervell, Stephens, Stonewall, Tarrant, Taylor, Terry, Throckmorton, Titus, Upshur, Van Zandt, Wichita, Wilbarger, Wise, Wood, Yoakum, and Young.

(c) The area included in the following counties constitutes the Central Zone: Anderson, Angelina, Bastrop, Bell, Blanco, Bosque, Brazos, Brown, Burleson, Burnet, Cherokee, Coke, Coleman, Comanche, Concho, Coryell, Crane, Crockett, Culberson, Ector, El Paso, Falls, Freestone, Gillespie, Glasscock, Grimes, Hamilton, Hardin, Houston, Hudspeth, Irion, Jasper, Jeff Davis, Kimble, Lampasas, Lee, Leon, Liberty, Limestone, Llano, Loving, McLennan, McCulloch, Madison, Mason, Menard, Midland, Milam, Mills, Montgomery, Nacogdoches, Newton, Orange, Pecos, Polk, Reagan, Reeves, Robertson, Runnels, Sabine, San Augustine, San Jacinto, San Saba, Schleicher, Shelby, Sterling, Sutton, Tom Green, Travis, Trinity, Tyler, Upton, Walker, Ward, Washington, Williamson, and Winkler.

(d) The area included in the following counties constitutes the South Central Zone: Aransas, Atascosa, Austin, Bandera, Bee, Bexar, Brazoria, Brewster, Caldwell, Calhoun, Chambers, Colorado, Comal, DeWitt, Dimmit, Edwards, Fayette, Fort Bend, Frio, Galveston, Goliad, Gonzales, Guadalupe, Harris, Hays, Jackson, Jefferson, Karnes, Kendall, Kerr, Kinney, LaSalle, Lavaca, Live Oak, McMullen, Matagorda, Maverick, Medina, Presidio, Real, Refugio, Terrell, Uvalde, Val Verde, Victoria, Waller, Wharton, Wilson, and Zavala.

(e) The area included in the following counties constitutes the South Zone: Brooks, Cameron, Duval, Hidalgo, Jim Hogg, Jim Wells, Kenedy, Kleberg, Nueces, San Patricio, Starr, Webb, Willacy, and Zapata.