Established by an act of Congress on September 7, 1916, it was named after Ahsiniiwin (Stone Child, incorrectly originally translated as Rocky Boy), the chief of the Chippewa band, who had died a few months earlier.

It was established for landless Chippewa (Ojibwe) Indians in the American West, but within a short period of time many Cree (nēhiyaw) and Métis were also settled there.

According to the map of Montana, the reservation takes in land within the boundaries of Hill and Chouteau counties, about 40 miles (64 km) south of the Canada–United States border.

Chief Rocky Boy (Ahsiniiwin) worked with Republican Senator Joseph M. Dixon, writer Frank Bird Linderman, and other influential individuals in Montana, including painter Charles Russell, to achieve his goal.

Chief Little Bear soon followed Rocky Boy with his own band, arriving with about 200 Cree from Canada after the North-West Rebellion.

The US Army had allowed the Chippewa and other landless Indians, including Cree refugees, to settle at Fort Assinniboine in Hill County.

With Frank Linderman leading many of the European-American supporters, the US Congress passed legislation in 1916 to establish what was first called Rocky Boy's Reservation.

Churchill asked the Department of Interior to withdraw all of Valley County from white settlement in order to establish a new closed Chippewa reservation there.

[citation needed] Chippewa notation : According to the papers of Indian agent Frank Bird Linderman (1869-1938),[7] Chief Rocky Boy died at Ft. Assiniboine on April 18, 1916.

[citation needed] But Robert Gopher (Blackfeet), an oral historian of the Chippewa, says that Rocky Boy was assassinated by rival Cree who used poison roots.

In 1917 a census was conducted at Rocky Boy Reservation in order to establish a tribal roll for what became known as the Chippewa Cree Tribe.

Other enterprises include Chippewa Cree Construction Company (20), Chippewa Cree Construction Corporation (14), National Tribal Development Association (9), Northern Winz Casino (70), and RJS & Associates (4), The tribe operates and administers its own educational system: the Rocky Boy public schools with 184 teachers and staff.

Plain Green and similar companies owned by other tribes have been criticized for profiting from high-interest online loans (called predatory lending).

[14] The Business Committee is effectively the Tribal Council and the governing body of the Tribe; it is dominated by Chippewa Cree adoptees.

Feeling displaced in Rocky Boy, the Chippewa have continued to practice their traditions on Hill 57, outside Great Falls, Montana.

(notation: In the BIA technical report on the Little Shell: "the Chippewa included a small and distinct group, centered around the Gopher family, some of whom are still resident of "hill 57" today.

Joseph W. Bailey Sr. was joined by Christian youth groups from around the country; together they built a new sanctuary and outdoor chapel, and started work on a retreat center.

Opponents of tribal termination noted the problems of the settlement, which occurred after allotment of communal lands had left members disadvantaged.

They believe that the tribal immunity from civil suits does not apply to individuals who do not have blood descent in a historic tribe, but claim adoptee status on a reservation.

Little Bear's involvement in the Frog Lake Massacre is the subject of the book, Blood Red The Sun, by William B. Cameron, among a handful of captives taken by the Cree band, which continued to elude Canadian law authorities.

[citation needed] There were two distinct rolls, the 1908 census of the Rocky Boy Band of Chippewa, was conducted near Helena, MT by Thralls B.

In 1914, Chief Rocky Boy was corresponding with Interior Secretary Franklin Lane, and expressed the Chippewa band's neutrality in the World War I conflict.

<64th Congress>: Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That the Act approved February eleventh, nineteen hundred and fifteen (Thirty-eighth Statutes at Large, page eight hundred and seven), entitled "An Act authorizing the Secretary of the Interior to survey the lands of the abandoned Fort Assinniboine Military Reservation and open the same to settlement," be, and the same is hereby, amended by the addition thereto of the following sections:

That fractional townships twenty-eight north, ranges fifteen and sixteen east, and fractional townships twenty-nine north, ranges fourteen and fifteen east, Montana principal meridian, within the boundaries of said reservation, embracing a total area of approximately fifty-six thousand and thirty-five acres, are hereby set apart as a reservation for Rocky Boy's Band of Chippewas and such other homeless Indians in the State of Montana as the Secretary of the Interior may see fit to locate thereon, and the said Secretary is authorized, in his discretion, to allot the lands within the reservation hereby created under the provisions of the general allotment Act of February eighth, eighteen hundred and eighty-seven (Twenty"fourth Statutes at Large, page three hundred and eighty-eight), as amended.

Because they were not directly enumerated in the Wheat census, Chief Rocky Boy inserted the language of the Act to include Big Rock's extended family.

On his death bed, and his last letter to Frank B. Linderman, Rocky Boy stated "I don't know if I will ever see you again, Little Bear (referring to their inclusion, along with Metis led by Kennawash)... is trying to get them all in.

Ethnological report on the Chippewa Cree tribe of the Rocky Boy Reservation and the Little Shell band of Indians / [by] John C. Ewers.

Ewers wrote "it will be for courts to decide if a Chippewa Cree tribe existed prior to 1935," foretelling the contemporary conflict.

In late 2014, Glenn Gopher, an oral historian and enrolled member of the Blackfeet Tribe, of Great Falls, Duncan Standing Rock Sr., and Rocky Boy Jr. Slimjohn (Deceased: 02/16/2017), of White Swan, Washington, oversaw the effort of the Rocky Boy Band of Chippewa to assert their sovereignty in a historic return to self-government.

The interim council consists of blood descendants of the Blackfeet Tribe, Browning, Montana, and of the original Rocky Boy's Band of Chippewa Indians, who will audit the largely adoptee roll.