The Sihásapa or "Blackfoot Sioux" are a division of the Titonwan, or Teton (also known as Lakota) Sioux

Sioux

The Sioux are Native American and First Nations people in North America. The term can refer to any ethnic group within the Great Sioux Nation or any of the nation's many language dialects...

.

Sihásapa is the Lakota

Lakota language

Lakota is a Siouan language spoken by the Lakota people of the Sioux tribes. While generally taught and considered by speakers as a separate language, Lakota is mutually understandable with the other two languages , and is considered by most linguists one of the three major varieties of the Sioux...

 word for "Blackfoot", whereas Siksiká has the same meaning in the Blackfoot language

Blackfoot language

Blackfoot, also known as Siksika , Pikanii, and Blackfeet, is the Algonquian language spoken by the Blackfoot tribes of Native Americans, who currently live in the northwestern plains of North America...

. Therefore, both nations have the same English name and sometimes are confused with one another.

The Sihásapa lived in the western Dakotas on the Great Plains

Great Plains

The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...

, and consequently are among the Plains Indians

Plains Indians

The Plains Indians are the Indigenous peoples who live on the plains and rolling hills of the Great Plains of North America. Their colorful equestrian culture and resistance to White domination have made the Plains Indians an archetype in literature and art for American Indians everywhere.Plains...

.
Their official residence today is the Cheyenne River Reservation in South Dakota, home also to the Itazipco (No Bows), the Minneconjou (People Who Live Near Water)and Oohenumpa (Two Kettle), all bands of the Lakota.