35 ILCS 200/10-145

Each farm dwelling and appurtenant structures and the tract upon which they are immediately situated shall be assessed by the local assessing officials at 33 1/3% of fair cash value except that in counties that classify property for purposes of taxation in accordance with Section 4 of Article IX of the Constitution they shall be assessed at the percentage of fair cash value as required by county ordinance. That assessment shall be subject to equalization by the Department under Sections 17-5 through 17-30.