1911 Encyclopædia Britannica/Blackfoot
BLACKFOOT (Siksika), a tribe and confederacy of North American Indians of Algonquian stock. The name is explained as an allusion to their leggings being observed by the whites to have become blackened by marching over the freshly burned prairie. Their range was around the headwaters of the Missouri, from the Yellowstone northward to the North Saskatchewan and westward to the Rockies. The confederacy consisted of three tribes, the Blackfoot or Siksika proper, the Kaina and the Piegan. During the early years of the 19th century the Blackfoots were one of the strongest Indian confederacies of the northwest, numbering some 40,000. At the beginning of the 20th century there were about 5000, some in Montana and some in Canada.
See Jean L'Heureux, Customs and Religious Ideas of Blackfoot Indians in J. A. I., vol. xv. (1886); G. B. Grinnell, Blackfoot Lodge Tales (1892); G. Catlin, North American Indians (1876); Handbook of American Indians (Washington, 1907), under "Siksika."