Coleto Creek is formed by the confluence of Fifteen-Mile Creek and Twelve-Mile Creek (at 28°52' N, 97°14' W) in Victoria County and flows southeast for twenty-five miles to its mouth on the Guadalupe River, six miles south of Victoria (at 28°42' N, 97°01' W). The stream forms part of the county line between Goliad and Victoria counties. In the area flat to rolling prairie is surfaced by permeable sand that supports mesquite and a variety of prairie grasses. The creek is impounded to form Coleto Creek Reservoir, which lies on the boundary of Victoria and Goliad counties. The stream was known as Coleto Creek as early as 1836. That year Texas revolutionary forces under James W. Fannin were defeated by a division of the Mexican army commanded by José de Urrea at the battle of Coleto, which was fought 2½ miles southwest of its banks. In 1850, when Clinton became the county seat of DeWitt County, the headstreams of Coleto Creek were named Three-Mile Coleto, Five-Mile Coleto, Twelve-Mile Coleto, Fifteen-Mile Coleto (the main stream), and Eighteen-Mile Coleto, the names signifying the distance from the stream to the courthouse door at Clinton. Although Cuero became county seat in 1876, the headstreams in 1949 were still known by their distances from Clinton. By the 1960s, however, the headstreams were considered separate creeks on county maps, with no reference to Coleto Creek in their names.