750 ILCS 36/202: Exclusive, Continuing Jurisdiction.

(a) Except as otherwise provided in Section 204, a court of this State which has made a child-custody determination consistent with Section 201 or 203 has exclusive, continuing jurisdiction over the determination until:

(1) a court of this State determines that neither the child, the child's parents, and any person acting as a parent do not have a significant connection with this State and that substantial evidence is no longer available in this State concerning the child's care, protection, training, and personal relationships; or

(2) a court of this State or a court of another state determines that the child, the child's parents, and any person acting as a parent do not presently reside in this State.

(b) A court of this State which has made a child-custody determination and does not have exclusive, continuing jurisdiction under this Section may modify that determination only if it has jurisdiction to make an initial determination under Section 201.

(c) A court of this State shall continue to exercise exclusive jurisdiction and be considered the home state of a child if a parent moves with a child under subsection (h) of Section 609.2 of the Illinois Marriage and Dissolution of Marriage Act.