Fort Concho was established during the American colonization of Texas in the 19th century. Europeans had first reached the Concho River valley in the 16th century. The Spanish established contact and then trade with the Jumano people, who were driven out of the valley in the 1690s by the Apache peoples. The Apache were themselves expelled by the mid-18th century by the Comanche. But in 1849, American colonists began crossing West Texas in large numbers to reach California, where gold had been discovered. To protect its citizens, the United States Army's Department of Texas ordered the construction of a string of forts along the frontier's routes of travel in 1851. Among those forts was Fort Chadbourne, established on October 28, 1852, and among those avenues was the Butterfield Overland Mail route, established in 1858 to bring mail from St. Louis to San Francisco. On its way through Texas, the route passed through Fort Chadbourne, which served as one of its stations, and then followed the Middle Concho River west. The beginning of the American Civil War in 1861 ended both enterprises. The Butterfield route moved out of Texas, and the federal government abandoned its Texas forts to the Confederate States of America.