The Cook County Assessor, pursuant to a county ordinance, classifies real estate for assessment purposes. In determining which classification is appropriate, the Assessor looks to the actual use of the property.

Class 1:
Vacant raw land without any improvements. Assessed at 10% of fair market value.

Class 2:
Single/family dwellings, co-ops, residential condominiums, apartment buildings of six/units or less, certain commercial buildings with some residential usage and farmland*. Assessed at 10% of fair market value.
*Farmland is not subject to the state multiplier.

Class 3:
Residential apartment buildings containing seven units or more. Assessed at 10% of fair market value.

Class 4:
Real estate owed by a not/for/profit agency which is used for not/for/profit purposes. Assessed at 20% of fair market value. This assessment rate became effective January 1, 2018. 

Class 5a:
Commercial real state. Assessed at 25% of fair market value.

Class 5b:
Industrial real estate. Assessed at 25% of fair market value.

Class 6b:
Industrial Incentive Classes

Class 7a:
Commercial Incentive Classes

Class 8:
Commercial/Industrial Incentive

Class 9:
Rehabbed Multi-Family Housing: Assessed at 10% of fair market value with operating expenses stabilized to reflect higher operating cost.