They have also populated parts of Alberta and southwestern Manitoba in Canada, and northern Montana and western North Dakota in the United States.

They transliterated many Cree or Ojibwe exonyms for other western Canadian indigenous peoples during the early colonial era.

Their ancient rivals the Ojibwe, knew of these as a new people and they start calling them Asini Pwat meaning "Stone Dakota."

Some writers believed that the name was derived from the Ojibway term assin, stone, and the French bouillir, to boil, but such an etymology is very unlikely.

[7] The Assiniboine and Sioux were both gradually pushed westward onto the plains from the woodlands of Minnesota by the Ojibwe, who had acquired firearms from their French allies.

Later, the Assiniboine acquired horses via raiding and trading with neighboring tribes of Plains Indians such as the Crow and the Sioux on their south.

The first person of European descent to describe the Assiniboine was an employee of the Hudson's Bay Company named Henry Kelsey in the 1690s.

Later explorers and traders Jean Baptiste de La Vérendrye and his sons (1730s), Anthony Henday (1754–55), and Alexander Henry the younger (1800s) confirmed that the Assiniboine held a vast territory across the northern plains, including into the United States (which achieved independence in 1776 but did not acquire the plains until 1803 in the Louisiana Purchase from France.)

[8] The Lewis and Clark Expedition was mounted by the United States in 1804–1806 to explore the Louisiana Territory, newly acquired from France.

The expedition's journals mention the Assiniboine, whom the party heard about while returning from Fort Clatsop down the Missouri River.

Among those who encountered and painted the Assiniboine from life were painters Karl Bodmer, Paul Kane, and George Catlin.

[9] In 1885, some Assiniboine scouts aided the Canadian North West Field Force track down Cree renegades who were participating in the Second Riel Rebellion of Métis.

[10] In 1857, a group of Sioux warriors, including Sitting Bull, attacked an Assiniboine camp, they had killed all except an 11-year-old boy who was still fighting against the raiders with his child-sized bow.

Members included the Assiniboine, Stoney (téhą nakóda or į́yąȟe wįcášta), the Plains and Woodland Cree, Saulteaux (called iʾášijabina), as well as Métis (sakná), and individual Iroquois people who traveled west as employees for the fur traders.

Loosely associated for military shelter against the Blackfoot and to ensure safe access to the prairies for the bison hunt were Plateau tribes such as Bitterroot Salish (Flathead) (pámnaska), Kutenai, Sekani, Secwepemc, and Nez Perce (pasú oȟnóga).

It posed a major threat to Indian nations not associated with it, such as the Shoshone (snohéna wįcášta) and Crow (kąǧí tóga or tógabi = "enemies") further south.

The women processed and preserved the meat for winter, and used hides, tendons, and horns for clothing, bedding, tools, cord and other items.

Though fighting in war has mostly been left to the boys and men, occasionally women have fought as well – both in battles and in defense of the home – especially if the tribe was severely threatened.

As a patrilineal tribe hereditary leadership passes through the male line, and children are considered to belong to the father and his clan.

Ikotme kills a frog who challenges his plans to create an endless winter but eventually yields and shortens the length to seven months.

Today, a substantial number of Assiniboine people live jointly with other tribes, such as the Plains Cree, Saulteaux, Sioux and Gros Ventre, in several reservations in Canada and the United States.

In March 2012, these two reservations has received 63 American bison from Yellowstone National Park, to be released to a 2,100-acre game preserve 25 miles north of Poplar.

The Assiniboine and Gros Ventre tribes at the Fort Belknap Indian Reservation will also receive a portion of this herd.