New religious movements were adopted during the early reservation period—first the Ghost Dance and later peyotism. Both were syncretic, combining elements of traditional religions with those of Christianity. The Ghost Dance began as a redemptive movement in the Great Basin culture area but became quite millenarian as it spread to the Plains, where believers danced in the hopes that the settlers would disappear, that the buffalo would return, and that their people would be impervious to attack. Concerns that Ghost Dancing would reignite the Plains Wars led to the massacre at Wounded Knee in 1890, in which more than 200 Miniconjou Sioux were killed by the reconstituted U.S. 7th Cavalry. This was the final major armed engagement of the Plains Wars.

Peyotism centred on a type of cactus—the peyote—the fruit of which caused hallucinations or visions when eaten or imbibed. As both the government and Christian missionaries considered this practice dangerous, they made efforts to suppress it. However, adherents of the peyote religion were incorporated in 1918 as the Native American Church, which continued to be a strong organization in the early 21st century. Sun Dance ceremonies, which had been subject to similar efforts at suppression, also continued to be practiced in the early 21st century.

Canadian tribes were also affected by development and particularly by the political changes that flowed from the British creation of the Dominion of Canada in 1867. The new Canadian government quickly stated its intent to annex the northern Plains, most of which had until then been part of Rupert’s Land, a territory of the Hudson’s Bay Company; annexation proceeded without consultation with the area’s resident tribes.

Powerful groups such as the Plains Cree, Blackfoot, Saulteaux, and Métis knew that annexation presaged the potential destruction of their way of life; many of these groups had provided refuge to tribes fleeing the conflicts in the United States and were well informed regarding the processes and consequences of colonial expansion. The Métis soon instigated the Red River Rebellion (1869–70); as a result, the Canadian government and the rebels agreed that the latter would have a strong presence in provincial government. Canada’s Numbered Treaties were subsequently executed; similar to the first Fort Laramie treaty, these agreements delineated tribal and governmental title to lands and the terms of development in the area, among other things. In 1885 a second rebellion was instigated in response to the repression of local rule, but it was quashed and its leaders hanged or imprisoned.

By the end of the 19th century both the United States and Canada had begun to pursue assimilationist programs designed to replace traditional cultures with Euro-American ways of life. Those sent to implement these programs were often corrupt or incompetent, and even the most professional among them encountered many obstacles: the nomadic groups were loath to become sedentary, cattle were universally derided as a poor substitute for buffalo, and reservation land was often unsuitable for agriculture. Cultivation was traditionally women’s work and the basis of their economic empowerment, and women and men alike resisted the change in the division of labour brought by the plow. Confusion resulted when officials insisted on listing families by surnames, which few indigenous peoples used. Additional misunderstandings arose within the matrilineal tribes when Euro-Americans insisted that property should pass from father to son rather than from mother to daughter.

Government-sponsored boarding schools were also given the mission of assimilating indigenous children. Attendance was mandatory and children were forced to leave their homes for months or years at a time. Some staff members used extremely harsh measures to force children to give up their traditional cultures and languages. The extent of abuse that occurred in these institutions, including sexual abuse, is perhaps best represented by the Canadian government’s 2006 offer of some $2 billion in reparations to former residential school pupils.

Sovereignty, economic development, and cultural revitalization

Assimilationist policies such as those mandating confinement to reservations were governmental challenges to tribal sovereignty; regaining self-determination in these and other areas became the defining goal of the Plains tribes in the 20th and 21st centuries. Many tribes in the United States were economically devastated by the Pick-Sloan plan, a post-World War II federal development program that placed major dams on the Missouri River and numerous smaller dams on its tributaries. This project flooded hundreds of square miles of the tribes’ most economically productive land and forced the relocation of some 1,000 extended-family households. The dams also created lakes so large that they were difficult to bridge, thus isolating reservation communities whose residents had once been able to visit with relative ease.

As with other rural communities, many Plains tribes had instituted formal plans for economic growth by the late 20th and early 21st centuries. Many of these plans were designed to resolve common rural development issues, such as underemployment and lack of services, while also instituting programs for cultural revitalization. For instance, when tribal schools were opened to replace the boarding schools, many employed tribal elders to instruct children in indigenous languages. Several tribes implemented buffalo ranching operations with programs that were intended to aid in the restoration of the Plains ecosystem. A number of groups own casinos and hotels (see Native American gaming); other tribal enterprises include manufacturing, trucking, and construction. See also Native American: History; Native American: Developments in the late 20th and early 21st centuries.