Fort Sill's early years were shaped by President Grant's Quaker peace policy, which assigned pacifist agents to oversee the reservation tribes and forbade soldiers from punishing raiders. The Kiowa and Comanche interpreted this restraint as weakness and used Fort Sill as a sanctuary between raids into Texas. In 1871, General of the Army William Tecumseh Sherman arrived at the post and learned of the Warren Wagon Train Raid, in which seven muleskinners had been killed. When the Indian Agent brought Kiowa chiefs to discuss the attack on Colonel Grierson's porch, Sherman ordered their arrest. Two chiefs attempted to assassinate him on the spot. Three were taken: Satank, Satanta, and Addo-ete. During the escort south to stand trial in Texas, Satank began his death song, seized a trooper's carbine, and was killed a mile down the trail. A marker on Berry Road still notes where the honored warrior fell.

In June 1874, the U.S. Army launched the Red River War against non-reservation Comanche, Kiowa, and Southern Cheyenne. Five columns converged on the Texas Panhandle in a strategy of relentless pursuit. Colonel Ranald Mackenzie led the Fourth Cavalry north from Fort Concho. Colonel Nelson Miles brought infantry and cavalry south from Fort Dodge. As many as twenty engagements scattered across the Panhandle through the fall of 1874. The Indians, traveling with families, mostly tried to avoid the soldiers, but even successful escapes cost them horses, food, and shelter that could not be replaced. Without a chance to graze their livestock and facing the disappearance of the buffalo herds, the bands surrendered one by one. Quanah Parker and his Kwahadi Comanches were the last to arrive at Fort Sill, in June 1875, ending Indian warfare on the South Plains.

In 1915, the 1st Aero Squadron arrived at Fort Sill under Captain Benjamin Foulois. They uncrated and assembled brand-new Curtiss JN-2 biplanes, pushed them downhill to the polo field, and on August 10 made their first flights. Two days later came the first crash -- the post paymaster, Captain George Knox, was killed. By November the squadron had successfully tested aerial photography and completed a photo mosaic of 42 plates. On November 19, they departed on the first squadron cross-country flight in Army history, six biplanes flying 439 miles to Fort Sam Houston, Texas. Months later, the squadron followed General Pershing into Mexico to chase Pancho Villa, flying 540 missions before their aircraft broke down. The 1st Aero Squadron went on to France as the first American aviation unit deployed overseas. Fort Sill's Henry Post Army Airfield, established in 1917, remains the oldest continuously operating airfield in the U.S. Army.

Fort Sill was declared a National Historic Landmark in 1960. Its most powerful landmark may be the Post Cemetery at the intersection of Macomb and Geronimo Roads. Unlike most military cemeteries of its era, it was never segregated. Indian chiefs who signed the Medicine Lodge Treaty rest beside troopers of the 10th Cavalry Regiment -- the Buffalo Soldiers -- who died at Fort Sill. Officers, enlisted men, spouses, and children lie side by side regardless of race. Geronimo's grave is the most visited. Beneath Henry Post Army Airfield lies another cemetery, more controversial: the old Indian Agency Cemetery, its headstones removed in the 1950s and the ground covered with earth to reduce hazards for aircraft. In 1984, archaeologist Towanna Spivey identified 64 of its occupants by name, with another 50 listed as unknown. Out of respect, none of the remains have ever been disturbed.

Today Fort Sill covers nearly 94,000 acres and serves as headquarters of the U.S. Army Fires Center of Excellence, training over 20,000 soldiers annually in field artillery, air defense artillery, and electronic warfare. The Field Artillery School, founded in 1911 as the School of Fire, is world-renowned. A Marine Corps detachment trains alongside Army artillerymen. The Artillery Half Section, an eight-man mounted unit with eight horses named after former commanding generals, re-creates World War I-era horse-drawn artillery at ceremonies and parades. Fort Sill has participated in every major U.S. conflict since its founding, evolving from a frontier cavalry post to a facility that still shapes how America fights. Among its unexpected alumni: Stephen Hillenburg, born at the fort in 1961, who grew up to create SpongeBob SquarePants.