After their victory in Red Cloud's War and with the signing of the Treaty of Fort Laramie (1868), the Lakota and their Northern Cheyenne allies were allocated a reservation including the Black Hills, in Dakota Territory and a large area of "unceded territory" in what became Montana and Wyoming.
Both areas were for the exclusive use of the Indians, and non-Indians (except for US government officials) were forbidden to trespass.
In 1874, the discovery of gold in the Black Hills caused the US government to attempt to buy the Black Hills from the Indians.
The US ordered all bands of Lakota and Cheyenne to come to the agencies on the reservation by January 31, 1876 to negotiate the sale.
A few bands did not comply and when the deadline of January 31 passed the US forced Sitting Bull, Crazy Horse, and their followers onto the reservation.
The first military expedition against the Indians in March 1876 was a failure, ending in the Battle of Powder River.

In June 1876, the US military renewed the fight with a three-pronged invasion of the Bighorn and Powder river country.
Colonel John Gibbon led a force from the west; General Alfred Terry (with Lieutenant Colonel George Armstrong Custer) came from the east; and General George Crook advanced northward from Fort Fetterman, near present-day Douglas, Wyoming.
The objective of the converging columns was to find the Indians and force them onto the reservation.
Crook's force, called the Bighorn and Yellowstone Expedition, consisted of 993 cavalry and mule-mounted infantry, 197 civilian packers and teamsters, 65 Montana miners, three scouts, and five journalists.
Crook's much-valued chief scout was Frank Grouard.
Among the teamsters was Calamity Jane, disguised as a man.

Crook left Fort Fetterman on the abandoned Bozeman Trail past the scene of many battles during Red Cloud's War ten years earlier.
His force reached the Tongue River near present-day Sheridan, Wyoming on June 8.
Crazy Horse warned that he would fight if "Three Stars" [Crook] crossed the Tongue and on June 9 the Indians launched a long distance attack, firing into the soldier's camp and wounding two men.
Crook and his men waited near the Tongue for several days for Crow and Shoshoni warriors to join his army.
175 Crow and 86 Shoshoni showed up on June 14 with Frank Grouard.
They welcomed the opportunity to strike a blow against their old enemies although they warned Crook that the Lakota and Cheyenne were as "numerous as grass."
The Shoshoni and Crow were well-armed.
Crook had made his reputation as an Indian fighter "using Indians to catch Indians" and the Crow and Shoshoni warriors were important to him.

On June 16, leaving his wagon and pack train behind with most of the civilians as a guard, Crook and the soldiers, with the Crow and Shoshoni in the lead, advanced northward beyond the Tongue to the headwaters of Rosebud Creek to search for and engage the Lakota and Cheyenne.
Each soldier carried four days' rations and 100 rounds of ammunition.
Crook's intention to make a quiet march was spoiled when the Crow and Shoshoni encountered a buffalo herd and shot many of them.
Crook anticipated that he would soon find a large Indian village on Rosebud Creek to attack, but the Indian village was on Ash Creek, west of Rosebud Creek.
Crook also underestimated the determination of his foe.
He anticipated the usual Indian tactics of hit-and-run encounters and ambushes, not a pitched battle.

The Indian force of almost 1,000 men set out from their village on June 16 in the middle of the night to seek out the soldiers on the Rosebud.
They rode all night, rested their horses for a couple of hours, then continued, making contact with Crook's scouts at about 8:30 am, June 17.
After their victory in Red Cloud's War and with the signing of the Treaty of Fort Laramie (1868), the Lakota and their Northern Cheyenne allies were allocated a reservation including the Black Hills, in Dakota Territory and a large area of "unceded territory" in what became Montana and Wyoming. Both areas were for the exclusive use of the Indians, and non-Indians (except for US government officials) were forbidden to trespass. In 1874, the discovery of gold in the Black Hills caused the US government to attempt to buy the Black Hills from the Indians. The US ordered all bands of Lakota and Cheyenne to come to the agencies on the reservation by January 31, 1876 to negotiate the sale. A few bands did not comply and when the deadline of January 31 passed the US forced Sitting Bull, Crazy Horse, and their followers onto the reservation. The first military expedition against the Indians in March 1876 was a failure, ending in the Battle of Powder River.
In June 1876, the US military renewed the fight with a three-pronged invasion of the Bighorn and Powder river country. Colonel John Gibbon led a force from the west; General Alfred Terry (with Lieutenant Colonel George Armstrong Custer) came from the east; and General George Crook advanced northward from Fort Fetterman, near present-day Douglas, Wyoming. The objective of the converging columns was to find the Indians and force them onto the reservation. Crook's force, called the Bighorn and Yellowstone Expedition, consisted of 993 cavalry and mule-mounted infantry, 197 civilian packers and teamsters, 65 Montana miners, three scouts, and five journalists. Crook's much-valued chief scout was Frank Grouard. Among the teamsters was Calamity Jane, disguised as a man.
Crook left Fort Fetterman on the abandoned Bozeman Trail past the scene of many battles during Red Cloud's War ten years earlier. His force reached the Tongue River near present-day Sheridan, Wyoming on June 8. Crazy Horse warned that he would fight if "Three Stars" [Crook] crossed the Tongue and on June 9 the Indians launched a long distance attack, firing into the soldier's camp and wounding two men. Crook and his men waited near the Tongue for several days for Crow and Shoshoni warriors to join his army. 175 Crow and 86 Shoshoni showed up on June 14 with Frank Grouard. They welcomed the opportunity to strike a blow against their old enemies although they warned Crook that the Lakota and Cheyenne were as "numerous as grass." The Shoshoni and Crow were well-armed. Crook had made his reputation as an Indian fighter "using Indians to catch Indians" and the Crow and Shoshoni warriors were important to him.
On June 16, leaving his wagon and pack train behind with most of the civilians as a guard, Crook and the soldiers, with the Crow and Shoshoni in the lead, advanced northward beyond the Tongue to the headwaters of Rosebud Creek to search for and engage the Lakota and Cheyenne. Each soldier carried four days' rations and 100 rounds of ammunition. Crook's intention to make a quiet march was spoiled when the Crow and Shoshoni encountered a buffalo herd and shot many of them. Crook anticipated that he would soon find a large Indian village on Rosebud Creek to attack, but the Indian village was on Ash Creek, west of Rosebud Creek. Crook also underestimated the determination of his foe. He anticipated the usual Indian tactics of hit-and-run encounters and ambushes, not a pitched battle.
The Indian force of almost 1,000 men set out from their village on June 16 in the middle of the night to seek out the soldiers on the Rosebud. They rode all night, rested their horses for a couple of hours, then continued, making contact with Crook's scouts at about 8:30 am, June 17.
Battle of the Rosebud