25 U.S.C. §§ 181–183

No white man, not otherwise a member of any tribe of Indians, who may after August 9, 1888, marry an Indian woman, member of any Indian tribe in the United States, or any of its Territories except the Five Civilized Tribes in the Indian Territory, shall by such marriage after August 9, 1888, acquire any right to any tribal property, privilege, or interest whatever to which any member of such tribe is entitled.

Every Indian woman, member of any such tribe of Indians, who may be married after August 9, 1888, to any citizen of the United States, is hereby declared to become by such marriage a citizen of the United States, with all the rights, privileges, and immunities of any such citizen, being a married woman: Provided, That nothing in sections 181 to 183 of this title contained shall impair or in any way affect the right or title of such married woman to any tribal property or any interest therein.

Whenever the marriage of any white man with any Indian woman, a member of any such tribe of Indians, is required or offered to be proved in any judicial proceeding, evidence of the admission of such fact by the party against whom the proceeding is had, or evidence of general repute, or of cohabitation as married persons, or any other circumstantial or presumptive evidence from which the fact may be inferred, shall be competent.