The Assiniboine, also known by the Ojibwe name Asiniibwaan "Stone Sioux", and the Cree as Asinîpwât are a Siouan Native American/First Nations people originally from the Northern Great Plains of the United States and Canada, centered in present-day Saskatchewan; they also populated parts of Alberta, southwestern Manitoba, northern Montana and western North Dakota. They were well known throughout much of the late 1700s and early 1800s. Images of Assiniboine people were painted by such 19th century artists as Karl Bodmer and George Catlin. The Assiniboine have many similarities to the Lakota Sioux in lifestyle, linguistics, and cultural habits, and are considered part of the Nakoda sub-group of the Nakota Sioux. It is believed that the Assiniboine broke away from Yanktonai Nakota in the 16th century. They are also closely linked to the Stoney First Nations people of Alberta - who are also Siouan people who use a Nakodan variant of the Sioux language.
The Assiniboine were close allies and trading partners of the Cree, engaging in wars against the Atsina alongside them, and later fighting the Blackfeet. A Plains people, they generally went no further north than the North Saskatchewan River and purchased a great deal of European trade goods through Cree middlemen from the Hudson's Bay Company.
The life style of this group was semi-nomadic, and they would follow the herds of bison during the warmer months. They did a considerable amount of trading with European traders, and worked with the Mandan, Hidatsa, and Arikara tribes, and that factor is strongly attached to their life style.
Though their description of the group was not all together favorable, the tribe's existence was noted in the journals of Lewis and Clark on their return journey from Fort Clatsop down the Missouri River. They had heard rumors that this was a ferocious group, and hoped to avoid contact with them. They did not see any of these people, and were not able to prove those rumors.
The names by which the Assiniboine are usually known are not derived from the way they refer to themselves. As a Siouan people, they traditionally thought of themselves to themselves as the Hohe Nakota. With the widespread adoption of English, however, many simply use the English name consistently. Assiniboine, however, is a word that English borrowed from French, which in turn took it from the Ojibwe word asinii-bwaan , meaning stone Sioux as well as the Cree term asinîpwât. In the same way, Assnipwan comes from the word asinīpwāt in the western Cree dialects, from asiniy - "stone" - and pwāta - "Sioux". Early French traders in the west were often familiar with Algonquian languages, and many Cree or Ojibwe words for other western Canadian peoples were adopted into French in the early colonial era, and thence into English.
They were referred with the name "stone" because they cooked with primarily stones. They would drop hot stones into water, causing the water to boil, which would cook the meat.
Today, a substantial number of Assiniboine people live jointly with several branches of the Sioux people on the Fort Peck Indian Reservation in northeastern Montana, and with the Gros Ventre people on the Fort Belknap Indian Reservation in north central Montana.
Canada Steamship Lines paid tribute to them by naming one of their new ships CSL Assiniboine.