West virginia constitution
Article VI: the legislature
Section 5

Until the senatorial districts shall be altered by the Legislature as herein prescribed, the counties of Hancock, Brooke and Ohio, shall constitute the first senatorial district; Marshall, Wetzel and Marion, the second; Ritchie, Doddridge, Harrison, Gilmer and Calhoun, the third; Tyler, Pleasants, Wood and Wirt, the fourth; Jackson, Mason, Putnam and Roane, the fifth; Kanawha, Clay, Nicholas, Braxton and Webster, the sixth; Cabell, Wayne, Lincoln, Boone, Logan, Wyoming, McDowell and Mercer, the seventh; Monroe, Greenbrier, Summers, Pocahontas, Fayette and Raleigh, the eighth; Lewis, Randolph, Upshur, Barbour, Taylor and Tucker, the ninth; Preston and Monongalia, the tenth; Hampshire, Mineral, Hardy, Grant and Pendleton, the eleventh; Berkeley, Morgan and Jefferson, the twelfth.