25 CFR § 5.1 - Definitions.
For purposes of making appointments to vacancies in all positions in the Bureau of Indian Affairs a preference will be extended to persons of Indian descent who are:
(a) Members of any recognized Indian tribe now under Federal Jurisdiction;
(b) Descendants of such members who were, on June 1, 1934, residing within the present boundaries of any Indian reservation;
(c) All others of one-half or more Indian blood of tribes indigenous to the United States;
(d) Eskimos and other aboriginal people of Alaska; and
(e) For one (1) year or until the Osage Tribe has formally organized, whichever comes first, effective January 5, 1989, a person of at least one-quarter degree Indian ancestry of the Osage Tribe of Indians, whose rolls were closed by an act of Congress.