Mustang was an important trading post in southeastern Washington County, three or four miles east or northeast of Brenham; its exact location is unknown. (Map location above approximate.) By 1837 Mustang had grown from a trading post into a small community, one of the first in Washington County during the early period of Anglo-American settlement. This locality was named for Mabry B. (Mustang) Gray, who had worked in a store there before gaining renown as a Texas Ranger and frontier Indian fighter and later as the subject of a novel, Mustang Gray: A Romance (1858), by Jeremiah Clemens. In the early 1830s William B. Travis lived in Mustang while he served as a lawyer in the alcalde's court. The Mustang community, which had developed around the trading post by 1837, did not long survive due to the attraction of other growing communities. The exact cause of Mustang's eventual disappearance is unknown, but growth of the nearby Cedar Creek village may have hastened Mustang's decline. No remains of Mustang exist. Source: Handbook of Texas Online.
Mustang 1915. Seventy-eight years ago Mustang was a trading point three miles east of Brenham. Mustang Gray, the celebrated Texas ranger, lived here and clerked in a store, and the place was named for him. W. B. Travis, the hero of the Alamo, lived in Mustang and practiced law in the alcalde's court in the early '30s. Its end is shrouded in obscurity. - The History of Brenham and Washington County, 1915 by Mrs. R. E. Pennington