525 ILCS 30/16
A register of areas is established. The register consists of areas registered by the Department under this Act with the approval of the Commission and the owner.
A registered area may be in public or private ownership and may or may not be proposed for public acquisition. A registered area may include a dedicated area.
The register shall include areas determined by the Commission to be worthy of preservation for the public purposes and policies set forth in this Act. The manner of registration of areas and of protection, control and management of registered areas shall be as provided by rules. No natural area shall be construed to be unworthy of preservation because it is not registered. Publication of the register is notice to all persons that the registered areas are worthy of preservation.
525 ILCS 30/16