The attack on a Northern Cheyenne and Oglala Lakota Indian encampment by Colonel Joseph J. Reynolds initiated the Great Sioux War of 1876.

Although destroying a large amount of Indian property, the attack was poorly carried out and solidified Northern Cheyenne and Lakota Sioux resistance to the U.S. attempt to force them to sell the Black Hills and live on a reservation.

Some of the bands did not comply and when the deadline of January 31 passed, the Commissioner of Indian Affairs, John Q. Smith, wrote that "without the receipt of any news of Sitting Bull's submission, I see no reason why... military operations against him should not commence at once."

Crook's force consisted of 883 men, including United States Cavalry and Infantry, civilian packers, scouts, guides, and a newspaper reporter.

[8] In frigid weather, Reynolds' plan was for one battalion, Companies I and K, of the 2nd U.S. Cavalry under the command of Captain Henry E. Noyes, to descend the steep hills south of where the second field hospital would be established to the valley floor.

The other company (I), under Captain Noyes, was to capture the Indian pony herd estimated at 1,000 animals, grazing and spread out through the valley on both sides of the river.

First Lieutenant John Gregory Bourke, General Crook's aide-de-camp, commented on the richness of the goods in the village: "bales of fur, buffalo robes, and hides decorated with porcupine quills".

The battle had lasted five hours when, at approximately 2:00 p.m., with the destruction of the village complete, Reynolds ordered his soldiers to withdraw, and the men made their way across to the east side of the frozen Powder River.

The last action of the battle took place about 1 mile (1.6 km) south of Hospital bluff, when First Lieutenant William C. Rawolle, commanding the rear guard, Company E, 2nd Cavalry, dismounted eight of his men in a defensive skirmish line.

In Reynolds' premature haste to withdraw, he left behind the bodies of three dead soldiers, with one in the village, and two at the second field Hospital as well as the badly wounded Private Ayers.

However, General Crook with the other four companies and the pack train was not there, as he had camped ten miles to the northeast and had failed to inform Colonel Reynolds of his location.

The women and children walked several days to reach the Oglala Sioux village of Crazy Horse farther north near the Little Powder River, where they were given shelter and food.

His friend and West Point classmate, President Ulysses S. Grant remitted the sentence, but Joseph J. Reynolds never served again.

Crook's and Reynolds' failed expedition and their inability to seriously damage the Lakota and Cheyenne at Powder River probably encouraged Indian resistance to the demands of the United States.

In 1919, a historian named Walter M. Camp learned that while the four soldiers killed in the battle had been left on the field, no headstones had been erected.

In a January 1920 address by Camp to the Order of the Indian Wars in Washington, D.C., he stated that the headstones would "be placed on the battlefield next summer."

In October 1933, Camp's 1920 address was reprinted in "Winners of the West," and came to the attention of D.C. Wilhelm of Gillette, Wyoming, who informed the writer that the headstones were still in storage.

In early 1934, with help from the American Legion, Montana State Senator Frank T. Kelsey, and others, a stone and concrete monument embedded with the soldiers' headstones was placed on the Powder River Battlefield.

United States Army, Big Horn Expedition Powder River Detachment, March 16–18, 1876, Colonel Joseph J. Reynolds, 3rd Cavalry, commanding

In 1951, Hollywood produced a fictional movie starring Van Heflin, Yvonne De Carlo, Jack Oakie, and Rock Hudson, released in the United States under the name Tomahawk.