SUPPLEJACK CREEK. Supplejack Creek rises at the intersection of Alternate U.S. Highway 77 and State Highway 95, just north of Yoakum in western Lavaca County (at 29°19' N, 97°09' W). It flows southeast through Yoakum and on for seventeen miles to its mouth on Clarks Creek, two miles northeast of the intersection of Highway 77 and State Highway 111 (at 29°13' N, 96°58' W). Its course is through poorly drained sandy upland prairie soils used primarily as rangeland for cattle. Vegetation consists of a fairly dense cover of scrub oak and mesquite that provides excellent habitat for wildlife, especially deer.