By 1875, Fort Concho had become one of the main US Army bases in Texas, but early in the year the 4th Cavalry was transferred to Fort Sill to keep the South Plains nations on their reservation. They were replaced in Texas by the 10th Cavalry, one of the two cavalry units of the "Buffalo Soldiers", commanded by Colonel Benjamin Grierson. Grierson arrived at Fort Concho on April 17, 1875, and established the regimental headquarters there. Stationed at Forts Concho, Stockton, Fort Davis, Quitman, and Clark, the 4th Cavalry was tasked with patrolling the frontier, escorting wagons and settlers, and mounting expeditions. Their surveys and patrols were invaluable for the development of West Texas, as roads could be built and telegraph lines laid. In July 1877, Captain Nicholas M. Nolan led an ill-fated expedition out of Fort Concho that achieved nothing and killed four soldiers from the 10th Cavalry's Company A.