The Northern Blacklands Boll Weevil Eradication Zone shall consist of the following area: all of Montague, Cooke, Grayson, Fannin, Lamar, Red River, Bowie, Cass, Morris, Titus, Franklin, Hopkins, Delta, Hunt, Rockwall, Collin, Denton, Wise, Jack, Parker, Tarrant, Dallas, Kaufman, Rains, Van Zandt, Henderson, Navarro, Ellis, Johnson, Hood, Somervell, Bosque, Hamilton, and Hill counties; and those parts of McLennan and Limestone counties north of State Highway 84.