Robert Douglas of the Geographical Board of Canada (1933) made several comments as to its origin: "The name commemorates the Assiniboine natives called by La Vérendrye in 1730 'Assiniboils' and by Governor Knight in 1715 of the Hudson's Bay Company 'stone Indians.'

"[4] The Assiniboine River rises in eastern Saskatchewan east of the community of Kelvington on the upper prairie level above the Manitoba Escarpment.

The glacial flows created a large delta east of Brandon extending almost to Portage la Prairie.

The Assiniboine winds its way east eventually joining the Red River at "The Forks" in Winnipeg, Manitoba.

[6] One millimeter of runoff from half the watershed would take 70 hours to drain at flow rates of 360 cubic metres per second (13,000 cu ft/s).

Despite these efforts, in May 2011 it was necessary to breach one of the dikes beside the river to relieve flood stresses east of Portage la Prairie.

A Manitoba-wide state of emergency was declared in the wake of one in three hundred-year floods on the Assiniboine River at Brandon.