25 C.F.R. § 23.110 : Indians — BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR — HUMAN SERVICES — INDIAN CHILD WELFARE ACT — INDIAN CHILD WELFARE ACT PROCEEDINGS —PRETRIAL REQUIREMENTS — When must a State court dismiss an action?

Subject to 25 U.S.C. 1919 (Agreements between States and Indian Tribes) and § 23.113 (emergency proceedings), the following limitations on a State court's jurisdiction apply:

(a) The court in any voluntary or involuntary child-custody proceeding involving an Indian child must determine the residence and domicile of the Indian child. If either the residence or domicile is on a reservation where the Tribe exercises exclusive jurisdiction over child-custody proceedings, the State court must expeditiously notify the Tribal court of the pending dismissal based on the Tribe's exclusive jurisdiction, dismiss the State-court child-custody proceeding, and ensure that the Tribal court is sent all information regarding the Indian child-custody proceeding, including, but not limited to, the pleadings and any court record.
(b) If the child is a ward of a Tribal court, the State court must expeditiously notify the Tribal court of the pending dismissal, dismiss the State-court child-custody proceeding, and ensure that the Tribal court is sent all information regarding the Indian child-custody proceeding, including, but not limited to, the pleadings and any court record.

25 C.F.R. §23.110

81 FR 38867, 12/12/2016