Bismark

Tom Green County (G-12) comprises 1,540.5 square miles in west central Texas. The county seat, San Angelo, is centrally located at 31?28' north latitude and 100?26' west longitude, 301 miles south of Amarillo and 258 miles west of Dallas. The county has a 235-day growing season, an average temperature range of 32? F in January and 97? F in July, an average annual precipitation of 18.2 inches, and an elevation variation of 1,717 feet to 2,480 feet. The principal river in the county is the Concho, which is formed by the convergence of the North, Middle, and South Concho rivers. The North Concho River and its tributaries, Bald Eagle, Chalk, Dry, Grape, Little, Mulberry, and Walnut creeks, drain the northwest portion of the county. The Middle Concho and its tributaries, Brushy, Dove, Dry Rocky, East Rocky, West Rocky, and Spring creeks, drain the west central and southwest portions of the county. The South Concho and its tributaries, Burks and Pecan creeks, drain the southern part of the county. And finally the Concho and its tributaries, Catelan, Erica, Hog Marsh, Kickapoo, Lipan, and Snake creeks, drain the southeastern part of the county. There are three major impoundments, O. C. Fisher lake, Twin Buttes Reservoir, and Lake Nasworthy. The major soil types in the county are silty clay loams and stony clays. The county has two distinct physiographic regions: the Osage Plains and the Edwards Plateau