In the early 1780's, smallpox had spread to Indigenous groups who were located along the Saskatchewan River.
The origins of this smallpox outbreak can be traced back to Mexico in 1779.
This smallpox outbreak was part of a larger epidemic of smallpox which originated in Mexico in 1779 and influenced the outcome of the American Revolution.
The high morality rate of the epidemic resulted in an unprecedented period of territorial and demographic change. The Niitsitapi (Blackfoot) saw their territory expand in the wake of the epidemic, while some tribes were devastated by mortality rates reaching as high as 75%. Along the North Saskatchewan River the Assiniboine were hit particularly hard. Either directly after this epidemic or shortly afterward, within a year or two, the U'Basqui'au, Pegogamaw, Cowinetow, and the Basqui Cree ceased to exist as cultural identities. By the turn of the century the Muskego and Anishinabe migrated to the lower Saskatchewan Valley
High mortality rates resulted in an unprecedented period of territorial and demographic changes