Carroll County, IL
P.O. Box 227
Mt. Carroll, IL 61053

Office Main Phone:
(815) 244-0237
Fax: (815) 244-1046
Office Hours: 8:30 am - 4:30 pm, Monday - Friday

The Assessment Office is responsible for the mass appraisal of all real property in Carroll County. The Assessment Office administers the following exemptions: owner-occupied, homestead, homestead improvement and senior assessment freeze. Exemptions for churches, government bodies and not-for-profit organizations are also kept on file. Sales information and sales reports are compiled for public use. Property record cards are kept up to date with a picture of the property and the appraisal information. There are 13321 parcels at this time. Maps are maintained in the GIS Department showing property ownership.

The Board of Review has three members. Complaints on assessments can be filed with the board of review for 30 days after the Supervisor of Assessments publishes the values in the paper and sends notices.

Duties of the Chief County Assessment Office include:

  • Holds annual meeting with Township Assessors
  • Serve as chairperson of the Farmland Assessment Review Committee
  • Serve as Clerk of the Board of Review
  • Maintains an up-to-date property record card system, which lists the legal description, Owner's name and the assessment
  • Maintains the current owners of record by using the deeds filed in the recorder's office
  • Equalize assessments by township
  • Publish the assessment changes for each township
  • Mail notices to each owner of record whose assessment has been changed
  • Apply the following preferential assessments:
    • General Homestead
    • Homestead Improvement
    • Senior Citizen Homestead
    • Senior Citizen Assessment Freeze
    • Disabled Veterans
    • Disabled Persons
    • Returning Veterans

What is an equalization factor or multiplier?

Equalization is the application of a uniform percentage increase or decrease to assessed values in order to bring assessment levels, on average, to a uniform level of market value.  Per the Illinois Property Tax Code assessments are statutorily required to be at 33 1/3% of fair cash (market) value.  For a detailed explanation of the equalization process, please refer to the Department of Revenue "Publication 136 - Property Assessment and Equalization", use the link below to view this publication.

Important Assessment Forms

Assessment_Web  Assessment Publications

MP900411753(1)_WebUnderstanding Equalization Factors


The filing deadline for the Senior Citizens Assessment Freeze for the 2021 Assessment Year is JULY 1, 2021.