At the time of the 1863 treaty the majority of the members of the Pembina Band were living and hunting in the area ceded in the Red River Valley, and a portion of the members were living further west on lands around the Turtle Mountains and Mouse River. It has been argued that at the time of the 1863 Treaty, the Pembina Band comprised two groups: one group under Chief Red Bear, and a second group under Chief Little Shell II. Both chiefs signed the Treaty as a 'Pembina Chief', and both had followers in attendance with them, so it can be argued that both groups were parties to the treaty. This observation seems validated by Governor Ramsey, who negotiated the 1863 treaty for the United States, referring to the 'Pembina Bands' as retaining a tract of country to the west of the ceded area. Over time, the two Pembina groups merged into one, under the leadership of Little Shell III.
After the treaty, a significant number of Pembina people continued to live in the Red River Valley but, in 1873, the United States purchased a township on the White Earth Reservation in Minnesota as a home for Pembina Indians with the hope of relocating them there. While most resisted the move to White Earth, some members of the Pembina Band were removed to White Earth, and others were placed on the Red Lake Reservation. However, the majority remained in North Dakota, relocating to the Turtle Mountain area. The Pembina Indians who remained were often interchangeably referred to as Pembina Chippewa; Turtle Mountain Band of Pembina Chippewa; Turtle Mountain Band of Chippewa; Little Shell's Band, and other variations of these names. In 1882, the President by Executive Order established a reservation at Turtle Mountain, with a diminishment occurring in 1884. At that time, the name Turtle Mountain Band of Chippewa was firmly established and the use of the ‘Pembina’ designation was dropped.
Little Shell III’s identity as a Turtle Mountain chief is demonstrated by a memorial of the Chippewa Indians of Turtle Mountain, Dakota Territory, filed with the Senate on February 23, 1876, which was ratified by congress and acknowledged the territory claimed by his father in 1851, when the Red Lake Band and Pembina Band divided their territories along a line described by Red Lake Chief Little Rock. Little Shell claimed his territory as extended west from there to Devil's Lake, to the Missouri Coteau, and to Mouse River. Specifically, this area was described as being from the Red River to Salt River, thence up the main channel of Salt River to its head. Thence in a direct line to the place of stumps (Lake Chicot/Stump Lake) thence in a direct line to Poplar Grove (Graham’s Island), thence in a direct line to the Sheyenne River to a vague point, then to Dogden Butte, then north to the Mouse River and along Mouse River to the US/Canadian boundary, thence to the place of beginning. Little Shell reserved all this country as a hunting ground.
Source: Source: Indian Claims Commission Docket No. 18-A