35 ILCS 200/9-35
Except as provided in Section 5-1108 of the Counties Code, each supervisor of assessments shall prepare and maintain, in accordance with rules and procedures prescribed by the Department, tax maps and up-to-date lists of property owners' names and addresses and property record cards for all of the property in the county, and shall procure at regular intervals from the records maintained by the county recorder information relating to transfers of property. The supervisor of assessments shall not, however, duplicate the work of any full-time township assessor or multi-township assessor who maintains up-to-date and complete tax maps, ownership lists and property record cards in accordance with rules and procedures prescribed by the Department. This shall not preclude the maintenance of duplicate records in the supervisor of assessments' office. This Section shall not prohibit the preparation and setting up of a property record system (including appraisals) and property record cards as provided for in other Acts, but such system and records shall not be considered to be assessments nor limit the powers and duties of the assessors as provided by this Code. Systems and records or copies of them set up under other Acts may be maintained by the supervisor of assessments in his or her office. In preparing the original tax maps, lists and property record cards, he or she shall consult with the Department and the Department shall furnish to the officer such supplies and equipment as may, in its judgment, be necessary to set up the original set of maps, lists and records required by this Section.
35 ILCS 200/9-35