Assessment Office

The primary function of the Boone County Assessment Office is to oversee the fair and equitable valuation of the real property in the county. The County Assessment Office provides guidelines to the township assessors each year for valuing the property in their jurisdictions.

The Property Tax Cycle

The County Assessment Office is the second step in the Property Tax Cycle after the Boone County Township Assessors complete the first step of appraising the real property for tax purposes at one-third of market value. The County Assessment Office is required by the Property Tax Code to bring the valuation as made by the assessors to one-third of market value based on the three previous years sales history compared to the assessed values.

Upon completion of the review of the assessments, the assessment books are then turned over to the Boone County Board of Review. The Board of Review, the third step in the process, hears complaints from property owners. The County Assessment Office provides staff for the Board in completion of their appeal process. The staff also reports to the Illinois Department of Revenue after completion of each step in the process for the equalization process by the department.


The Boone County Assessment Office administers the Homestead Exemptions and the preferential assessments as provided in the Illinois Property Tax Code. The exemptions include the Owner-Occupied, the Senior Exemption, the Senior Freeze, the Disabled Persons, two Disabled Veterans Exemptions, the Returning Veterans Exemption and the Homestead Improvement Exemption.

The preferential assessments include the Model Home Assessment; Developer’s Discount, Conservation Stewardship, the Forestry Act, and Common Area, among others. Assessment office staff also completes preparation of the applications and renewals of the Public Exemptions or Non-Homestead Exemptions for the Board of Review and Department of Revenue.


Parcel Maintenance

The record of ownership for each parcel of land in the county has been maintained in the Boone County Assessment Office since 1971. This is a process that has continued plus the creation of new parcels since 1971. As well as transfer history the County Assessment Staff with the Mapping/GIS staff maintain the maps of all the parcels in the county.

Deeds and Real Estate Transfers

Deeds and real estate transfer declarations are filed in the Boone County Clerk’s Office and forwarded to the assessment office. These records are used for correspondence with the property owners, but also provide information as to the sales history of property. Copies of the transfer declarations are forwarded to the township assessors for them to use in the valuation process. They are also completed and sent to the Illinois Department of Revenue for the equalization process by the department.

Contact Us

1208 Logan Avenue Phone #:  815-544-2958 Email the Assessment Office
Belvidere, IL 61008   Hours: M-F 8:30a.m.-5:00p.m.