Although soldiers destroyed one Northern Cheyenne and Oglala Lakota village at the Battle of Powder River, the expedition solidified Lakota Sioux and Northern Cheyenne resistance against the United States attempt to force them to sell the Black Hills and live on a reservation, beginning the Great Sioux War of 1876.
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."
[5] In the early morning hours of March 3, 1876, north of Fort Fetterman, Indian warriors attacked the Big Horn Expedition's cattle herd, numbering over 200 animals.
This was reported to Crook, and at 5 p.m. on March 16, he divided his command and sent Colonel Joseph J. Reynolds (a West Point classmate of President Ulysses S. Grant, and a combat veteran of both the Mexican–American War, and Civil War) on a night march with about 383 men, supplying them with rations for one day, and following the trail of the two Oglala's southeast toward the Powder River.
General Crook kept with him about 300 of the expedition's men and the pack train, with which he planned to rendezvous with Reynolds at the mouth of Lodge Pole Creek on the 17th.
During the night Frank Grouard and the other scouts led Reynolds's advance and followed the two warriors's trail in the snow.
In his premature haste to withdraw, the command left behind the bodies of its three dead soldiers, with one in the village, and two at a field hospital as well as Private Lorenzo E. Ayers, who was badly wounded and subsequently killed by vengeful Indians.
[11] Although the Indians suffered only two to three killed and one to three wounded during the battle, they lost most of their property and, in the words of the Cheyenne warrior Wooden Leg, were "rendered very poor."
The people 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.
At approximately 1:30 p.m. that day, Crook's command rejoined Reynolds with the pack train, and the six companies were finally able to collect their rations and blankets.
The reunited column returned to the supply base at Old Fort Reno, where the wounded soldiers were placed in wagons, and Captain Coates's companies of the 4th Infantry rejoined the Big Horn Expedition after two weeks of separation.
Reynolds's friend and West Point classmate, President Ulysses S. Grant, remitted the sentence, but he never served again.
Joseph J. Reynolds retired on disability leave on June 25, 1877, exactly one year after the culminating battle of the Great Sioux War at the Little Bighorn.
Crook's and Reynolds' failed expedition and their inability to seriously damage the Lakota and Cheyenne probably encouraged Indian resistance to the demands of the United States.
United States Army Big Horn Expedition, March 1–26, 1876, Brigadier General George R. Crook and Colonel Joseph J. Reynolds, commanding.
In 1951, Hollywood produced a fictional movie loosely based upon the Battle of Powder River of the Big Horn Expedition, starring Van Heflin, Yvonne De Carlo, Jack Oakie, and Rock Hudson.