As a result, in 1851 the federal government brought many of the Plains tribes together at Fort Laramie, including many Lakota and Dakota bands, and sought to establish peace among the tribes so settlers could continue to move across the area and not fear for their safety. The government solution was to assign each tribe a defined territory where they were to remain. Government negotiators had the various Indian nations appoint head chiefs to these councils so they could deal with a small group of men rather than the entire nations. This sort of negotiation was meaningless to the Lakota, Dakota, and other Indian nations. Decision-making among the Lakota and Dakota was based on participation of all until consensus was reached, and in this form of democracy a few men could not speak for all or bind all people to treaty promises. Nonetheless, the government insisted on negotiating with appointed chiefs and through the treaty process sought to define its relationship with the various tribes. The 1851 Fort Laramie Treaty defined territory for each tribal group in order to end intertribal rivalry and it permitted travelers and railroad workers on the Platte River Road. The Yanktonai, covered by an earlier 1825 treaty, were omitted from the treaty because their traditional areas were far removed from the overland route to the Pacific Coast which the treaty aimed to safeguard.
Ultimately, many Lakota and Dakota never knew of the existence of the 1851 Treaty and they continued their intertribal raiding. The U.S. regarded this as a breach of treaty, however, and government could not compel its own countrymen to respect the treaty either. Travelers continuously passed through defined Indian territories and ignored the treaty though no major incidents occurred until the numbers of travelers increased.
A number of events that occurred in 1861 directly impacted both the Dakota and Lakota who would later to be part of the Standing Rock Reservation. In 1861 when the Dakota Territory was established, the Yanktonai and Hunkpatina occupied much of the area east of the Missouri River. Events which followed the Minnesota Indian War of 1862 rapidly changed this. Also, in 1861, gold was discovered at the headwater of the Missouri River and this had an immediate impact on the Lakota living on the west side of the Missouri River.
The Santee, located on an ever-shrinking homeland in Minnesota, were dissatisfied with federal policies and when they received no redress of their grievances some men precipitated a confrontation in 1862. Some Santees raided settlements, attacked a military installation, and ultimately caused 40,000 settlers to flee. Federal response to the trouble was quick and all Indians in the area were considered potentially dangerous, so many Indian people who had no connection to the troubles were punished. Fearful of retribution, many of the Santees fled into Dakota Territory and Canada. Settlers on the Dakota frontier, fearful of trouble, demanded government protection. Generals Henry Sibley and Alfred Sully were assigned to round up “hostiles” in the Dakotas. They found no “hostiles” but followed some hunting bands at various times. Despite the apparent peace in the Dakotas, wild rumors of dangerous Indians continued and the military was under great public and political pressure to keep up its campaign.