Mich. Comp. Laws § 722.26d

Sec. 6d. A third person filing an action under section 6c shall proceed as follows: (a) If the circuit court has continuing jurisdiction over the child, the action shall be filed in the circuit court that has continuing jurisdiction over the child. (b) If the circuit court does not have continuing jurisdiction over the child, the action shall be filed in the circuit court in the county where the child has resided for the 6 months immediately preceding the filing of the action or, if the child has not resided in any county for the 6 months immediately preceding the filing of the action, the action shall be filed in the circuit court in the county having the most significant connection with the child.