20 ILCS 3440/3.5
When an undertaking encounters human remains, unregistered graves, grave markers, or grave artifacts, all activities shall cease within a 100-foot radius of the encounter. The encountering party shall notify the coroner and the Department as required in Section 3. If the coroner determines that the human remains are not over 100 years old, no further action is required under this Act. If the coroner does determine that the human remains are over 100 years old, the Department shall review the undertaking and may issue a permit pursuant to Section 13. During its review, if it is determined by the Department that the human remains, unregistered grave, grave marker, or grave artifact are Native American in origin, the Department shall conduct tribal consultation with the tribal nations that identify as having or having had a historical, cultural, or geographic affiliation on the land where the undertaking will occur.
20 ILCS 3440/3.5