SMOOTHINGIRON BRANCH. Smoothingiron Branch rises one mile southeast of Sublime in northeastern Lavaca County (at 29°28' N, 96°46' W) and flows southwesterly for 3½ miles to its mouth on the Navidad River (at 29°25' N, 96°47' W). It drains an area known as Smoothing Iron Prairie. Soils in the gently rolling area are generally poorly draining sandy loam. Except where cleared, the area is heavily wooded with a mixture of oak, cedar, and yaupon that provides excellent wildlife habitat and is used primarily as unimproved range land for cattle.