225 ILCS 411/20-35

(a) The stacking of caskets underground of any individual is limited to no more than 3 caskets in one grave space with the exception of an arrangement made pursuant to a lawful contract with a consumer that complies with the requirements of Section 20-10 of this Act. (b) Burials and interments of unknown individuals or unknown body parts must be entered into the Cemetery Oversight Database as provided in Section 20-6 of this Act.