Killdeer Mountain

This clash, sometimes called the Battle of Tahkahokuty Mountain, unfolded on July 28 and 29, 1864, as part of Brig. Gen. Alfred Sully's campaign against the Sioux in Dakota Territory. Today the site falls within Dunn County, North Dakota. More than 4,000 soldiers took part in Sully's broader operation, with over 2,000 engaged directly in the fighting, making it the largest campaign the U.S. army ever mounted against Native Americans.

Background

The punishment inflicted on the Sioux by federal authorities following the Dakota War of 1862 extended even to bands that had taken no part in the fighting. Sizable expeditions sent into Dakota Territory during 1863 drove most Sioux across to the western bank of the Missouri and brought a measure of safety, though not complete security, to the settled frontier in Minnesota and the Dakotas. Even so, Sioux raiders killed four white settlers in the spring of 1864.

Behind the renewed military push against the Sioux lay a practical concern: keeping communication lines open to the newly found gold deposits in Montana and Idaho. Steamboats carrying miners depended on the Missouri River, which ran straight through Sioux lands, making that waterway essential to the mining effort.

That winter, spanning 1863 and 1864, Major General John Pope, who commanded Sully, directed him to build a series of forts along the Missouri and across the eastern Dakotas. The goal was twofold: protect the routes leading to the goldfields and remove the danger the Sioux posed to settlers living east of the river.

Sully organized his forces into two brigades. The First, numbering as many as 1,700 men, traced the Missouri's course starting from Sioux City, Iowa. Meanwhile the Second Brigade, roughly 1,550 strong, moved by land from Fort Ridgely in Minnesota. During the advance along the river, Sioux fighters killed one soldier and wounded another; the three men responsible were captured, killed, and beheaded. Steamboats, fifteen in total, carried extra troops and civilians up the Missouri to reinforce the ground campaign.

The two brigades came together on June 29, and by July 7 Sully had built Fort Rice in North Dakota along the Missouri, using it as a supply base reachable by steamboat for the expedition ahead. Scouts working for him, drawn from Winnebago, friendly Sioux, and mixed-blood communities, brought word of a massive Sioux camp some 130 miles to the northwest near the Little Missouri River. On July 19 Sully set out from Fort Rice in search of this encampment, burdened reluctantly with the task of escorting a wagon train carrying 200 miners and their families bound for the goldfields.

According to his scouts, the encampment held between 1,500 and 1,800 tipis. Sully anticipated facing somewhere between 5,000 and 6,000 warriors, though the Sioux themselves later put the number at 1,600, a figure that seems more accurate given the usual ratio of one or two grown men per tipi. The camp was composed largely of Lakota, specifically Hunkpapa, Sihasapa, Miniconjou, and Sans Arc bands, along with Yanktonais and a handful of Santees. Weaponry among the Sioux consisted mainly of bows and arrows, supplemented by a small number of short-range firearms. Notably, many of these people, particularly the Teton bands, had shown no previous hostility toward American forces.

After detaching men to hold Fort Rice and watch over the civilian train, Sully led 2,200 soldiers into the coming engagement, backed by two artillery batteries totaling eight howitzers.

On July 26, his Indian scouts clashed with a group of thirty Sioux warriors close to what is now Richardton, North Dakota, leaving one scout wounded. Aware that his presence was now known, Sully pressed forward with speed tempered by caution. Then, on the morning of July 28, a mixed-blood Santee scout named Frank LaFramboise brought news that the main Sioux camp lay just ten miles distant.

The terrain near Killdeer Mountain sat on the fringe of the badlands, marked by what was described as deep, impassable ravines and high, rugged hills. Recognizing that such broken ground would make any mounted charge impractical, Sully had his men dismount and arranged them into a hollow square measuring roughly a mile and a quarter, or about two kilometers, on each side. Horses and artillery pieces were kept safe within this formation. As his troops moved forward on foot, Sioux horsemen gathered in clusters along the flanks and atop the surrounding hills.

Battle

At long range the two forces traded jeers, with Sully's men formed into a hollow square while Native fighters spread across the surrounding hills. A Hunkpapa warrior named Lone Dog broke from the hills and rode close enough to taunt the troops within rifle distance. In response, Sully directed his sharpshooters to fire on him, though sources disagree about whether the shots struck Lone Dog or left him untouched.

Once the shooting toward Lone Dog began, the infantry pushed forward in a skirmish formation while Sioux riders probed the edges of the square looking for gaps to exploit. The army's artillery kept the Sioux from massing in force, and when warriors tried to strike at Sully's rear, a well placed shell scattered them and killed several. Despite these efforts, the square kept moving forward without breaking stride. Realizing they lacked the strength to reverse the soldiers' advance, the Sioux turned their attention instead to breaking camp, gathering their tipis and belongings, and shielding their women and children as they retreated.

In a final effort to slow Sully down, Sioux fighters charged both flanks of his formation, with Yanktonai and Santee warriors striking the right side and Teton warriors hitting the left. On the right flank, Major Alfred B. Brackett led his Minnesota Battalion in a mounted countercharge backed by artillery support. Fighting broke out at close range with sabers and pistols, and Brackett's men eventually drove the attackers back. During this clash, Lieutenant George Northrup, well known for his exploits on the frontier and in the Civil War, lost his life.

As dusk approached and Sully's force drew near the Sioux encampment, he called a halt for the night but kept his artillery firing on the village throughout the darkness. Facing this bombardment, the Sioux either fled or staged brief rearguard actions, leaving behind the bulk of their tipis and possessions.

By the day's end, Sully's command had suffered three killed and ten wounded. He placed Sioux losses somewhere between 100 and 150 dead, the vast majority of them warriors, though the Sioux themselves reported only 31 killed.

Killdeer Mountain Battlefield State Historic Site

The State Historical Society of North Dakota oversees a protected portion of the battlefield grounds, preserved today as a historic site. Visitors can find a monument made from a sandstone slab, along with a flagpole standing nearby. Two headstones on the grounds pay tribute to soldiers who lost their lives there: Sergeant George Northrup of Company C and Private Horace Austin of Company D, both from Brackett's Battalion, Minnesota Cavalry. The grounds sit 8.5 miles to the northwest of Killdeer, North Dakota.

Aftermath

Once the Sioux had cleared out of their camp the following day, Sully assigned 700 men to wipe out everything left behind. Tipis, huge stores of dried buffalo meat, and as many as 3,000 dogs fell to this destruction, the dogs being shot outright. Winnebago scouts also killed a handful of Sioux, children among them, who had stayed behind in the abandoned camp.

The bulk of the Sioux fled westward into the Dakota Badlands beyond Killdeer Mountain, though a portion lingered close to Sully's position. When several Sioux appeared on a hilltop displaying a white flag in hopes of parleying, soldiers opened fire instead, driving them off. During the night that followed, a Sioux war party struck Sully's picket guards, killing two and wounding a third. Separately, a soldier lost his life at the hands of his own guards after being taken for the enemy.

Despite dwindling supplies, Sully chose to press on after the Sioux. A Blackfoot scout claimed knowledge of a path through the Badlands wide enough for the wagon train to traverse. Following a two-day pause to rest, Sully's force ventured forward into the uncharted ground. The Sioux would go on to trouble their advance in what became known as the Battle of the Badlands.