The role of Fort Sill has evolved since Maj. Gen. Phillip H. Sheridan drove the first stake here in 1869. Fort Sill Soldiers originally protected settlers in Texas from raids by the Plains Indian tribes. Soldiers from famous units like the 7th Cavalry, led by Col. George A. Custer, and the 10th Cavalry, known as the Buffalo Soldiers, used Fort Sill as a base in the Indian Wars. As the tribes accepted peace with the U.S., Fort ...