215 ILCS 5/165
Within 15 days after such merger or consolidation has become effective, the surviving or new company shall file for record with the recorder of the county in which the principal office of any of the companies parties to the agreement is located in this State, the agreement of merger or consolidation, or copy thereof, certified by the Director, any certificate of approval issued by the Director, or copy thereof, certified by him and a certificate of merger or consolidation, as the case may be, or a copy thereof, certified by the Director, or by the official of the state or country that issued such certificate. The certificate of merger or consolidation, or a copy thereof so certified, shall also be recorded with the recorder of each other county in this State in which any of the companies parties to the agreement, shall have real property at the time of such merger or consolidation, the title to which will be transferred by the merger or consolidation.
215 ILCS 5/165