Apsáalooke oral tradition links the origin of the tribe to a separation from a parent group. Tradition relates that this group traveled extensively across the upper Midwest of the United States, and possibly into southern Canada. Eventually this parent group came under the leadership of two brothers known as No Intestines and Red Scout. These leaders had their respective followers and, even though they camped as one group, the two divisions were clearly defined within a single village. The group following No Intestines called themselves Apsáalooke people, "Our Side," and they would become the historic Apsáalooke who eventually settled in Montana and Wyoming. The group under Red Scout would move to the Heart River area of North Dakota. They would learn horticultural ways from the Mandan of that region, and would become the historic Hidatsa tribe.
In addition, Apsáalooke oral tradition lends religious validity to this separation of the Apsáalooke and Hidatsa. Their narratives relate how the two leaders had fasted at Devil’s Lake and each had received a vision. No Intestines received a vision that told him to seek the seeds of Sacred Tobacco, Ihchichiaee. Once locating this tobacco, he and his followers would be in the center of the world, the best place for his people. Red Scout, on the other hand, received a vision instructing him to settle with his people on the bluffs above the rivers, and to plant corn on the flood plains below.
After the initial vision, No Intestines and his followers began a long trek west. Eventually, the Apsáalooke people stopped near Chief Mountain, in present day Montana, and there No Intestines fasted again. On the fourth day he received a second vision telling him he was not yet at his destination, the area was too cold. Then the Apsáalooke people moved south, passing by Salt Lake, Utah. After a while, No Intestines and his group reached the Canadian River in Oklahoma, called Arrowhead River by the Apsáalooke . Here, No Intestines fasted again and was told to move north. So the Apsáalooke people headed north, following the Missouri to the Platte River, then trekking to the Powder River which they followed north until they reached the Big Horn Mountains in northern Wyoming.
To the Apsáalooke the highest peak on the crest of the Big Horn Mountains is called Awaxaawakússawishe, "Extended Mountain," and it is considered the center of their world. On this peak No Intestines fasted for the fourth time and received a vision telling him that he was in the right place that the tobacco seed could be found at the bottom of Awaxaawakússawishe. As he looked to the base of the mountain, he saw the seeds as "twinkling stars," ihkaxáaxaaheetak. The Apsáalooke people then made their home in Montana and Wyoming, with the Big Horn Mountains as their heartland.