The senior citizens homestead exemption (35 ILCS. Instructions: Mail (or submit in person) this application and supporting documents to a Cook County Assessor's Office.Senior Citizen Homestead Exemption. The Cook County Assessor's Office administers property tax exemptions that may contribute to lowering veteran's property tax bill. The BOR accepts exemption applications for approximately 30 days, four times each year. To apply, a homestead exemption application (DTE 105A) must be filed with the Auditor after January 1 and on or before December 31 in the year of application. Clark County Property Tax Inquiry ; Parcel Criteria. Parcel Number ; Address Criteria. The Illinois property tax cycle generally extends over a two-year period. There are a number of exemptions that can reduce assessed value (and therefore property tax payments) in Illinois.