Am I eligible for a property tax credit?
You may figure a credit for the Illinois property taxes you paid on your principal residence (not a vacation home or rental property) for the time you owned and lived at the property during the tax year, if that residence was in Illinois. Nonresidents of Illinois may not take this credit.
You may not figure a credit for mobile home privilege tax, penalties, or fees included in your property tax bill, or the portion of the property that is deductible as a business expense.
See the IL instructions for further details at http://tax.illinois.gov.