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The Hunkpapa ( Lakota: Húŋkpapȟa) are a Native American group, one of the seven council fires of the Lakota tribe. The name Húŋkpapȟa is a Lakota word meaning "Head of the Circle". (At one time, the tribe's name was represented in European-American records as Honkpapa.) By tradition, the Húŋkpapȟa set up their lodges at the entryway to the circle of the Great Council when the Sioux met in convocation.  They speak Lakȟóta, one of the three dialects of the Sioux language.
Seven hundred and fifty mounted Yankton, Yanktonai and Lakota joined six companies of the Sixth Infantry and 80 fur trappers in an attack on an Arikara Indian village at Grand River (now South Dakota) in August 1823, named the Arikara War. Members of the Lakota, a part of them "Ankpapat", were the first Native Americans to fight in the American Indian Wars alongside US forces west of the Missouri. 
They may have formed as a tribe within the Lakota relatively recently, as the first mention of the Hunkpapa in European-American historical records was from a treaty of 1825.
By signing the 1825 treaty, the Hunkpapa and the United States committed themselves to keep up the "friendship which has heretofore existed". With their x-mark, the chiefs also recognized the supremacy of the United States.  It is not certain whether they really understood the text in the document. The US representatives gave a medal to Little White Bear, who they understood was the principal Hunkpapa chief; they did not realize how decentralized Native American authority was. 
With the Vaccination Act of 1832, the United States assumed responsibility for the inoculation of the Indians against smallpox. Some visiting Hunkpapa may have benefitted from Dr. M. Martin's vaccination of about 900 southern Lakota (no divisions named) at the head of Medicine Creek that autumn.  When smallpox struck in 1837, it hit the Hunkpapa as the northernmost Lakota division. The loss, however, may have been fewer than one hundred people.  Overall, the Hunkpapa seem to have suffered less from new diseases than many other tribes did. 
The boundaries for the Lakota Indian territory were defined in the general peace treaty negotiated near Fort Laramie in the summer of 1851. Leaders of eight different tribes, often at odds with each other and each claiming large territories, signed the treaty. The United States was a ninth party to it. The Crow Indian territory included a tract of land north of the Yellowstone, while the Little Bighorn River ran through the heartland of the Crow country (now Montana). The treaty defines the land of the Arikara, the Hidatsa and the Mandan as a mutual area north of Heart River, partly encircled by the Missouri (now North Dakota). 
Soon enough the Hunkpapa and other Sioux attacked the Arikara and the two other so-called village tribes, just as they had done in the past. By 1854, these three smallpox-devastated tribes called for protection from the U.S. Army, and they would repeatedly do so almost to the end of inter-tribal warfare.  Eventually the Hunkpapa and other Lakota took control of the three tribes' area north of Heart River, forcing the village people to live in Like a Fishhook Village outside their treaty land. The Lakota were largely in control of the occupied area to 1876-1877. 
The United States Army General Warren estimated the population of the Hunkpapa Lakota at about 2920 in 1855. He described their territory as ranging "from the Big Cheyenne up to the Yellowstone, and west to the Black Hills. He states that they formerly intermarried extensively with the Cheyenne." He noted that they raided settlers along the Platte River.  In addition to dealing with warfare, they suffered considerable losses due to contact with Europeans and contracting of Eurasian infectious diseases to which they had no immunity.
The Great Sioux Reservation was established with a new treaty in 1868.  The Lakota agreed to the construction of "any railroad" outside their reservation. The United States recognized that "the country north of the North Platte River and east of the summits of the Big Horn Mountains" was unsold or unceded Indian territory.  These hunting grounds in the south and in the west of the new Lakota domain were used mainly by the Sicangu (Brule-Sioux) and the Oglala, living nearby.
The "free bands" of Hunkpapa favored campsites outside the unsold areas. They took a leading part in the westward enlargement of the range used by the Lakota in the late 1860s and the early 1870s at the expense of other tribes. In search for buffalo, Lakota regularly occupied the eastern part of the Crow Indian Reservation as far west as the Bighorn River, sometimes even raiding the Crow Agency, as they did in 1873.  The Lakota pressed the Crow Indians to the point that they reacted like other small tribes: they called for the U.S. Army to intervene and take actions against the intruders. 
In the late summer of 1873, the Hunkpapa boldly attacked the Seventh Cavalry in United States territory north of the Yellowstone. Custer's troops escorted a railroad surveying party here, due to similar attacks the year before.  Battles such as Honsinger Bluff and Pease Bottom took place on land purchased by the United States from the Crow tribe on May 7, 1868.  These continual attacks, and complaints from American Natives, prompted the Commissioner of Indian Affairs to assess the full situation on the northern plains. He said that the unfriendly Lakota roaming the land of other people should "be forced by the military to come in to the Great Sioux Reservation".  That was in 1873, notably one year before the discovery of gold in the Black Hills, but the US government did not take action on this concept until three years later.
Since the 1880s, most Hunkpapa have lived in the Standing Rock Indian Reservation (in North and South Dakota). It comprises land along the Grand River which had been used by the Arikara Indians in 1823; the Hunkpapa "won the west" half a century before the whites. 
During the 1870s, when the Native Americans of the Great Plains were fighting the United States, the Hunkpapa were led by Sitting Bull in the fighting, together with the Oglala Lakota. They were among the last of the tribes to go to the reservations. By 1891, the majority of Hunkpapa Lakota, about 571 people, resided in the Standing Rock Indian Reservation of North and South Dakota. Since then they have not been counted separately from the rest of the Lakota.
The Hunkpapa population was estimated to be around 1,600 men, women and children in 1805, corresponding to 160 tipis. Shihasapa and Sans Arc migration to Hunkpapa camps in the 1840s had doubled their number of tipis in 1849. From a height in 1855 with 360 lodges, the next decades were marked by a small decline. The decline was higher in percentage of the total Lakota population. In 1855, the total number of lodges were nearly 2,000. Fifteen years later only 315 tipis out of 2,400 were set up in Hunkpapa camps. 
- Bear's Rib, 19th century chief
- Leonard Lethbridge Sr. ''Itonka Ska'' (born 1931), subject in book Legends of Our Times by Morgan Baillargeon; artist of buffalo hide exhibit in the Smithsonian
- Dana Claxton (born 1959), Hunkapa Lakota filmmaker, photographer and performance artist
- Robert "Tree" Cody, flutist; enrolled member of the Maricopa tribe
- Zahn McClarnon, actor, whose mother was Hunkpapa Lakota; has had a continuing role on the series Longmire, among other work
- Phizí ( Gall), one of the commanders in the Battle of Little Bighorn
- Tȟatȟáŋka Íyotake ( Sitting Bull), chief and leader of the Lakota in fighting against the US Army to remain off the reservations in the 19th century 
- Tȟatȟóka Íŋyaŋke ( Running Antelope), Hunkpapa chief and advisor to Sitting Bull
- Maria Yellow Horse Brave Heart, Hunkpapa social worker responsible for developing historical trauma models and interventions for American Indian people
- "Hunkpapa Sioux Indian Tribe History", Handbook of American Indians, 1906, carried in Access Genealogy, accessed 9 Dec 2009
- Robinson, Doane: Official Correspondence Pertaining to the Leavenworth Expedition into South Dakota in 1823 for the Conquest of the Ree Indians. South Dakota Historical Collections, Vol. 1 (1902), pp. 179-256. Meyer, Roy W.: ;;The Village Indians of the Upper Missouri. The Mandans, Hidatsas and Arikaras;;. Lincoln and London, 1977, p.54.
- Kappler, Charles J.: Indian Affairs. Laws and Treaties. Washington, 1904, Vol.2, p.235. "Archived copy". Archived from the original on 2016-07-03. Retrieved 2016-08-13.CS1 maint: Archived copy as title ( link)
- Jensen, Richard E. & James S. Hutchins: Wheel Boats on the Missouri. The Journals and Documents of the Atkinson-O'Fallon Expedition, 1824-26. Helena and Lincoln, 2001, p.128.
- Trimble, Michael K.: "The 1832 Inoculation Program on the Missouri River". In Verano, John W. and D.H. Ubelaker (eds): Disease and Demography in the Americas. Washington and London, 1992, pp. 257-264.
- Bray, Kingsley M.: "Teton Sioux Population History, 1655-1881". Nebraska History, Summer 1994, Vol. 75, No. 2, p. 178, column II.
- Bray (1994), "Teton Sioux Population History, 1655-1881", p.184, column II.
- Kappler, Charles J.: Indian Affairs. Laws and Treaties. Washington, 1904. Vol. 2, p. 594. http://digital.library.okstate.edu/kappler/Vol2/treaties/sio0594.htm
- Meyer, Roy W.: The Village Indians of the Upper Missouri. The Mandans, Hidatsas and Arikaras. Lincoln and London, 1977, p. 106.
- Meyer (1977), The Village Indians, pp. 110-133.
- Larson, Robert W.: "Galls Last Stand", The Quarterly Journal of Military History, Autumn 2009, 22, 2, p. 46. Scott, Kim Allen and Ken Kempcke: "A Journey to the Heart of Darkness. John W. Wright and the War against the Sioux, 1863-1865", Montana, The Magazine of the West, Vol. 50, No. 4 (Winter 2000), pp.2-17.
- Kappler, Charles J.: Indian Affairs. Laws and Treaties. Washington, 1904. Vol. 2, pp. 998-1003. "Archived copy". Archived from the original on 2011-11-26. Retrieved 2013-10-07.CS1 maint: Archived copy as title ( link)
- Kappler, Charles J.: Indian Affairs. Laws and Treaties. Washington, 1904. Vol. 2, p. 1002.
- Linderman, Frank B.: Plenty Coups. Chief of the Crows. Lincoln/London, 1962, pp. 135-137. Algier, Keith: The Crow and the Eagle. A Tribal History from Lewis and Clark to Custer. Caldwell, 1993, pp. 320-326. McGinnis, Anthony: Counting Coup and Cutting Horses. Intertribal Warfare on the Northern Plains, 1738-1889. Evergreen, 1990, p. 137. Hoxie, Frederick E.: Parading Through History. The Making of the Crow Nation in America, 1805-1935. Cambridge, 1995, pp. 106-109. Serial set 1607. 43. Congress, 1st Session, House Executive Document, No. 89, pp.22-23.
- Hoxie, Frederick E.: Parading Through History. The Making of the Crow Nation in America, 1805-1935. Cambridge, 1995, p. 106. Ewers, John C.: "Intertribal Warfare as a Precursor of Indian-White Warfare on the Northern Great Plains", Western Historical Quarterly, Vol. 6, No. 4 (Oct. 1975), pp. 397-410. Serial set 1607, 43. Congress, 1st Session, House Executive Document, no. 89, pp. 23, 49.
- Howe, George Frederick: "Expedition to the Yellowstone River in 1873: Letters of a young Cavalry Officer", The Mississippi Valley Historical Review, Vol. 39, No. 3 (Dec. 1952), pp. 519-534.
- Hoxie, Frederick E.: Parading Through History. The Making of the Crow Nation in America, 1805-1935. Cambridge, 1995. See map p. 63. Kappler, Charles, J.: Indian Affairs. Laws and Treaties. Washington, 1904, Vol. 2. pp. 1008-1011 (treaty with the Crows 1868). American Memory. Indian Land Cessions in the United States, 1784 to 1894. Map: Montana 1. http://memory.loc.gov/cgi-bin/map[ permanent dead link]
- Kvasnicka, Robert M. and Herman J. Viola: The Commissioners of Indian Affairs, 1824-1977. Lincoln and London, 1979, p.145.
- Hoxie, Frederick E.: Parading Through History. The Making of the Crow Nation in America, 1805-1935. Cambridge, 1995, pp. 106-109. Dunlay, Thomas W.: Wolves for the Blue Soldiers. Indian Scouts and Auxiliaries with the United States Army, 1860-90. Lincoln and London, 1982, p. 113.
- White, Richard: "The Winning of the West: The Expansion of the Western Sioux in the Eighteenth and Nineteenth Centuries". The Journal of American History, Vol. 65, No. 2 (Sep. 1978), pp. 319-343.
- Bray, Kingsley M.: Teton Sioux Population History, 1655-1881. Nebraska History, Summer 1994, Vol. 75, No. 2, pp. 165-188.
- "Rosebud Sioux Tribe Community Environmental Profile". Archived from the original on May 16, 2008. Retrieved November 22, 2015.CS1 maint: Unfit url ( link)
- "Native American Tribes: Sioux (Second Part)", 1997, summarized by Willow Branch from "Through Indian Eyes", Readers' Digest (originally hosted by GeoCities; most links are dead)