Illinois has no statute equivalent to the California Mills Act. Instead, Illinois Property Tax Code 35 ILCS 200/15-40 and Cook County Class L assessment incentive provide property tax reductions for landmarked rehabilitation projects, freezing valuations rather than reducing rates.
California Mills Act contracts cap property taxes by formula for 10-year renewable terms. Illinois uses two parallel mechanisms. Statewide, 35 ILCS 200/15-40 Property Tax Assessment Freeze applies to owner-occupied historic residences listed on National Register or in certified districts, freezing assessed value for eight years then phasing back over four years. Cook County Class L extends a similar 12-year freeze on commercial or income-producing landmarks where rehab exceeds 50 percent of base value. Both require Illinois Historic Preservation Division certification of work meeting Secretary of Interior Standards. No formula-based ongoing valuation cap exists.
Falsifying rehab cost reports or failing to maintain qualifying status triggers retroactive recapture of the tax benefit. Owners owe back taxes plus interest. Class L recipients must complete approved scope before benefit activates.
Cook County, IL
Cook County Historic Preservation Ordinance Chapter 102 Article VI authorizes individual Landmark designation for properties of architectural, historical, or...
Cook County, IL
Cook County does not use Los Angeles-style Historic Preservation Overlay Zones. Instead, Cook County Historic Preservation Ordinance Chapter 102 Article VI e...
See how Cook County's mills act contracts rules stack up against other locations.
Help us keep this page accurate. If you notice an error or outdated information, let us know.