The Occaneechi Band of the Saponi Nation is a state-recognized tribe in North Carolina. 

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The Ocean Man First Nation is an Assiniboine, Cree, and Saulteaux band in southeastern Saskatchewan, Canada.

The Ochapowace Nation is a Cree First Nation in southern Saskatchewan, Canada.  

The O-Chi-Chak-Ko-Sipi First Nation is a band located on IR Crane River 51 in Manitoba.

The O'Chiese First Nation is a Saulteaux First Nation in Alberta, Canada, and speaks the Western Ojibwa language.

Odanak First Nation is a band in Quebec, Canada.

Oglala Sioux Tribe Tribal headquarters are based out of the Red Cloud building in the town of Pine Ridge.  

ENROLLED MEMBERS LIVING ON RESERVATION: 

19,639

Ohkay Owingeh ([ʔòhkèː ʔówĩ̂ŋgè], Navajo Kin Łichííʼ)  Pueblo located in New Mexioco

Ojibways of Onigaming First Nation is an Ojibwe or Ontario Saulteaux First Nation located in Kenora District, Ontario near Nestor Falls, Ontario.

Ojibways of the Pic River First Nation, now known as Biigtigong Nishnaabeg, is an Ojibway (Anishinaabe) First Nation on the northern shore of Lake Superior.

The Okanagan Indian Band is a First Nation in the Canadian province of British Columbia, located in the city of Vernon in the northern Okanagan Valley.

The Okanese First Nation is a Cree-Saulteaux First Nation band in Balcarres, Saskatchewan, Canada. 

Old Massett Village Council is a band of the Haida people located in Old Massett, on Haida Gwaii.

Omaha Tribe of Nebraska  A treaty  allowed the creation of the Nebraska Territory, and Omaha City was founded on July 4, 1854

One Arrow First Nation is a Cree First Nations band in Bellevue, Saskatchewan, Canada. Its main reserve is located just south of Batoche.

The Oneida were members of the Iroquos Five Nation Confederacy.  Two parts of the tribes migrated to Canada and one to Wisconsin.

Oneida A Good Heart A Good Mind A Good Fire.  Oneida Reservation located adjacent to Green Bay, WI.

The Oneida Nation of the Thames is an Onyota'a:ka (Oneida) First Nations band located in southwestern Ontario, a 30-minute drive from London.

The Onion Lake Cree Nation is a Plains Cree First Nations band in Canada, straddling the Saskatchewan-Alberta provincial border.

The Onondaga People ( "Hill Place") are one of the original five constituent nations of the  Iroquois Confederacy in northeast North America.

The Opaskwayak Cree Nation is a First Nations band located near The Pas, Manitoba, about 626 km North of Winnipeg.

The Oregon Jack Creek Band is a First Nations government in the Thompson Canyon area of the Southern Interior of the Canadian province of British Columbia.

Garyling is home to Holikachuk and Ingalik Indians.

Organized Village of Kake is located in the Prince of Wales-Hyder Census Area of Alaska.

Organized Village of Kasaan   Kasaan is a city in the Prince of Wales-Hyder Census Area in the U.S. state of Alaska. The population was 49.

Organized Village of Kwethluk    in Central Alaskan Yup'ik, is a city in Bethel Census Area in the U.S. state of Alaska. At the 2010 census the population was 721,

Organized Village of Saxman is locate in the Ketichikan Gateway Borough of Alaska.

The Orutsararmiut Native Council is a Federally recognized governing body for the community of Bethel, Alaska.

Oscarville Traditional Village lies 6 miles southwest of Bethel and 401 miles west of Anchorage. Oscarville is located in the Bethel Recording District and Bethel Census Area.

The Osoyoos Indian Band is a First Nation in the Canadian province of British Columbia, located in the town of Oliver and Osoyoos in the Okanagan Valley.

Otoe-Missouria Tribe of Indians are located in Oklahoma and their language is Chiwere part of the Siouan language family.

The Ottawa Tribe of Oklahoma is one of four federally recognized tribes of Odawa people in the United States.

Oujé-Bougoumou Cree Nation is a Cree First Nation in Quebec, Canada.