25 CFR § 23.109 - How should a State court determine an Indian child's Tribe when the child may be a member or eligible for membership in more than one Tribe?
(b) If the Indian child meets the definition of “Indian child” through more than one Tribe, deference should be given to the Tribe in which the Indian child is already a member, unless otherwise agreed to by the Tribes.
(c) If an Indian child meets the definition of “Indian child” through more than one Tribe because the child is a member in more than one Tribe or the child is not a member of but is eligible for membership in more than one Tribe, the court must provide the opportunity in any involuntary child-custody proceeding for the Tribes to determine which should be designated as the Indian child's Tribe.
(1) If the Tribes are able to reach an agreement, the agreed-upon Tribe should be designated as the Indian child's Tribe.
(2) If the Tribes are unable to reach an agreement, the State court designates, for the purposes of ICWA, the Indian Tribe with which the Indian child has the more significant contacts as the Indian child's Tribe, taking into consideration:
(i) Preference of the parents for membership of the child;
(iv) Interest asserted by each Tribe in the child-custody proceeding;
(v) Whether there has been a previous adjudication with respect to the child by a court of one of the Tribes; and
(vi) Self-identification by the child, if the child is of sufficient age and capacity to meaningfully self-identify.
(3) A determination of the Indian child's Tribe for purposes of ICWA and the regulations in this subpart do not constitute a determination for any other purpose.