In response to raids by tribes that had not signed treaties, Lieutenant George A. Custer was placed in charge of an expedition to find a good location for a military post in the Black Hills. Custer took 1,000 men with him and approached the hills from the north. In addition to military members, there were scientists, miners, newspaper journalists, and even musicians along on what must have been one of the best provisioned expeditions in U.S. history.

The expedition headed for the hills in July 1874. By July 30, two miners found traces of gold in French Creek. By August 12, the news was released by the military headquarters in St. Paul. By the time Custer returned to headquarters, just 60 days after he left, prospectors were already getting ready to violate the 1868 treaty and invade the tribal lands.

While the military was trying to keep trespassers out, the white settlers were demanding that the hills be opened and popular sentiment in Washington was with the settlers. Arrangements were made to bring many of the tribal chiefs to Washington to persuade them to part with the hills. The chiefs were noncommittal and returned home. A scientific expedition was then sent to the hills to determine their value for purposed of negotiation.

A Grand Council was held in September 1875. Thousands of Sioux showed up for the council and promptly rejected the $6 million offered for the Black Hills. They also rejected the proposal for an annual rental payment of $400,000 a year for the mining rights to the hills. In addition to the hills, the government asked the tribes to cede the Wyoming Big Horn Country. When the tribes rejected the offer, the government removed the cavalry from the region, opening the hills to the invasion of the prospectors and to a new round of Indian Wars.