From the website of the Illinois Historic Preservation Agency in regards to cemeteries--
The Illinois Historic Cemetery Handbook:A Guide to Basic Preservation was developed in response to many inquires to the Illinois Historic Preservation Agency (IHPA) and the Illinois Department of Natural Resources (IDNR). Most often, those questions focused on how to clean and repair gravestones, sources of assistance, and the laws that govern cemeteries.
More information can be found on the Agency's website.
