525 ILCS 33/10
As used in this Act:
"Conservation and recreation purposes" means activities that are consistent with the protection and preservation of open lands, natural areas, wetlands, prairies, forests, watersheds, resource-rich areas, greenways, and fish and wildlife habitats, including multiple use such as hunting, fishing, trapping, and other recreational uses.
"Conservation easement" means a nonpossessory interest in real property imposing limitations or affirmative obligations the purposes of which include retaining or protecting natural, scenic, or open-space values of real property, assuring its availability for forest, recreational, or open-space use, protecting natural resources, maintaining or enhancing air or water quality, or preserving the natural, historical, architectural, archaeological , or cultural aspects of real property. A conservation easement may be released at any time by mutual consent of the parties.
"Department" means the Department of Natural Resources.
"Natural area" means an area of land that either retains or has recovered to a substantial degree its original natural or primeval character, though it need not be completely undisturbed, or has floral, faunal, ecological, geological, or archaeological features of scientific, educational, scenic, or esthetic interest.
"Open space" means those undeveloped or minimally developed lands that conserve and protect valuable natural features or processes.
"Real property" means land, including improvements existing on the land.
"Units of local government" means counties, townships, municipalities, park districts, conservation districts, forest preserve districts, river conservancy districts, and any other units of local government empowered to expend public funds for the acquisition and development of land for public outdoor park, recreation, or conservation purposes.
525 ILCS 33/10