BIG MINERAL CREEK. Big Mineral Creek rises at the junction of its northern and southern branches two miles north of Whitesboro in western Grayson County (at 33°41' N, 96°54' W) and runs east for ten miles to its mouth on the Big Mineral arm of Lake Texoma, seven miles northwest of Southmayd (at 33°43' N, 96°46' W). The surrounding terrain is generally flat with occasional shallow depressions, surfaced by clay and sandy loams that support water-tolerant hardwoods, conifers, and various grasses. The region has served as range and cropland.