Brushy Creek rises three miles northwest of Leander in southwestern Williamson County (at 30°35' N, 97°51' W) and flows east for sixty-nine miles, through southern Williamson County and southwestern Milam County, to its mouth on the San Gabriel River, five miles north of Rockdale (at 30°43' N, 97°03' W). The stream is intermittent in its upper reaches. It was named Arroyo de las Ánimas Benditas (Creek of the Blessed Souls) by explorers Louis Juchereau de St. Denis and Domingo Ramón in 1716 and was known by variations of that name throughout the Spanish colonial period. It was the site of several of the earliest communities in the county. The battle of Brushy Creek occurred near its banks in 1839. The banks of the stream are heavily wooded for much of its length with mesquite and hardwood trees, and the creek flows through nearly level to gently rolling terrain surfaced by clayey and loamy soils used predominantly for agriculture.