How to Appeal Property Taxes in McHenry County, Illinois (2026 Guide)

McHenry County does not have one countywide 2026 assessment-appeal deadline. The deadline is 30 calendar days after your township assessment list is published; as of July 27, 2026, the next concrete deadline is Richmond Township: Thursday, August 6, 2026 at midnight, followed by Chemung on August 13 and Dorr on August 21. File with the McHenry County Board of Review / Office of Assessments, not with the Treasurer, using the county’s Board of Review complaint materials and evidence forms. (mchenrycountyil.gov)

How assessments work in McHenry County

Your 2026 assessment is for taxes payable in 2027; it is separate from the 2025 tax bill mailed in 2026. Illinois generally assesses property at 33 1/3% of fair cash value, and McHenry County’s township assessors value homes using prior sales, property characteristics, and local equalization. The county’s own Property Tax 101 example explains that the township assessor value should equal one-third of market value, and that a township equalization factor is applied when the sales-ratio study shows assessments are above or below that level. (mchenrycountyil.gov)

For 2026, McHenry County changed notice delivery: assessment notices are posted online, and notices are no longer mailed for properties changed only by an equalization factor. Notices are still mailed for revaluations, farmland, and new properties. The county says 2026 notices began posting July 7, 2026, staggered by township, so homeowners should use Devnet Wedge and sign up for notice alerts instead of waiting for mail. (mchenrycountyil.gov)

The appeal body is the McHenry County Board of Review. Its 2026 rules identify the Board as an intermediary between township assessors and taxpayers, with authority under the Illinois Property Tax Code to confirm, reduce, or increase assessments. The 2026 rules list Michael P.W. Grebenick, CIAO, as chairperson; Rebekkah Burtcher, CIAO, and Katie Biederer, CIAO, as members; and Alejandro Benitez as ex-officio clerk. (mchenrycountyil.gov)

Whether you should appeal

Appeal if the assessment, not the tax bill, is wrong. Divide your total assessed value by 0.3333 to estimate the market value the county is implying. If your 2026 total assessment is $150,000, the implied market value is about $450,000. If comparable homes near you were selling around $420,000 near January 1, 2026, you may have a market-value case.

A second common basis is uniformity: your home may be worth about what the assessor says, but similar homes may be assessed lower. McHenry’s residential attachment requires a subject column and at least three comparable properties; the county’s example warns that failing to complete the subject column can trigger an incomplete filing notice. (mchenrycountyil.gov)

Do not appeal just because tax rates are high. PTAB, the next appeal level after the county Board of Review, says it does not review the amount of the tax bill or the tax rate used to compute it. (ptab.illinois.gov)

Also check exemptions before appealing. McHenry County lists the General Homestead Exemption at up to $8,000 off EAV for owner-occupied homes owned and occupied as of January 1; the Senior Citizens Homestead Exemption at up to $8,000 off EAV for owners 65 or older; the Low-Income Senior Citizens Assessment Freeze for qualifying seniors with household income of $75,000 or less, due July 1 each year; the Persons with Disabilities Homestead Exemption at $2,000; veterans’ exemptions; and the Home Improvement Exemption excluding up to $25,000 of EAV increase for up to four years. (mchenrycountyil.gov)

Step-by-step how to file

1. Find your township deadline. The legal rule is 30 calendar days after publication of the assessment list. Current posted 2026 deadlines are: Richmond, published July 7, deadline August 6; Chemung, published July 14, deadline August 13; Dorr, published July 22, deadline August 21. Other township rows were still blank on the county deadline table as of this guide. (mchenrycountyil.gov)

2. Download the official materials. Use the county Forms and Rules page for the 2026 Board of Review Rules and complaint links/forms. The county’s indexed materials refer to the Official McHenry County Complaint Form and the Attachment to McHenry County Residential Complaint Form for residential comparable evidence. (mchenrycountyil.gov)

3. Assemble evidence. For a market appeal, use comparable sales of similar homes as close as possible to January 1, 2026. The 2026 rules say ideal sales are similar properties near that date, generally within 12 months before or after January 1, 2026, with broader dates accepted only at the Board’s discretion. For a property-record error, include the property record card, a statement identifying the incorrect data, and proof such as photos, a plat, floor plan, or construction documents. (mchenrycountyil.gov)

4. File before midnight / office close. County materials give the Board/Assessment Office address as McHenry County Office of Assessments, Administration Building, Suite 106, 2200 N. Seminary Ave., Woodstock, IL 60098-2698; the hearing location/office location is 667 Ware Road, Room/Suite 106, Woodstock, IL 60098; phone 815-334-4290; fax 815-334-4939; email assessments@mchenrycountyil.gov. (mchenrycountyil.gov)

5. Filing methods. The county’s public pages and forms provide email, mail, fax, and physical office information; use those official contacts unless the 2026 Forms and Rules page shows a specific complaint-upload link for your filing. I did not find an official McHenry County e-filing portal for initial Board of Review complaints separate from the forms page; the county does provide online lookup for submitted complaints and assessor responses. (mchenrycountyil.gov)

6. Fee. McHenry County’s official complaint pages and 2026 rules materials reviewed here do not list a homeowner filing fee for a Board of Review complaint. If you are near deadline, file first and call the Office of Assessments to confirm any current administrative requirement.

What happens after

If your filing is incomplete, the 2026 rules say the Board may send a Letter of Deficiency, giving 10 business days from the letter date to fix the problem; failing to cure it results in a No Change decision, which still preserves the ability to appeal to PTAB. (mchenrycountyil.gov)

A residential oral hearing is short. The 2026 rules say residential hearings where the complainant is present are scheduled for 15 minutes; commercial and industrial hearings get 30 minutes. The hearing is for valuation evidence, not a debate over tax bills or the property-tax system. (mchenrycountyil.gov)

The Board also uses non-hearing/document review. McHenry County’s annual report tracks both hearings and non-hearings, and its final-decision archive shows decisions by township after each cycle. The 2025 annual report says the county processed 1,258 taxpayer-generated assessment appeals for tax year 2025, down from 1,521 in 2024, but the county materials I found do not publish a homeowner success rate or median reduction. (mchenrycountyil.gov)

Expect decisions after the township work is complete, not at the hearing table. In the 2025 cycle, final decision mailing dates shown in the annual report ranged from late October 2025 through February 26, 2026, and the completed 2025 assessment roll was certified to the County Clerk on March 3, 2026. (mchenrycountyil.gov)

If you lose, you may appeal to the Illinois Property Tax Appeal Board within 30 days of the Board of Review’s written decision. PTAB says there is no charge for filing a PTAB appeal. (ptab.illinois.gov)

Local tips

Use the right tax-rate math. McHenry’s Property Tax 101 example uses a tax rate of 8.456274 per $100 of taxable EAV. If your appeal reduces market value from $450,000 to $420,000, the assessed value reduction is roughly $10,000 because Illinois assesses at one-third of market value. Estimated annual tax savings using that county example rate: $10,000 × 8.456274% = $845.63. Your parcel’s actual rate may differ because school, fire, library, park, municipal, and other districts vary by tax code. (mchenrycountyil.gov)

Do not wait for a mailed notice. For 2026, equalization-only notices may be online-only. Check Devnet Wedge by PIN or address and sign up for township alerts. (mchenrycountyil.gov)

Talk to your township assessor before filing. McHenry County’s assessment office says township assessors perform the local valuation work, while the county monitors compliance, applies equalization factors, and directs the appeal procedure. A square-footage, bathroom-count, basement, garage, or condition error may be easier to document before the formal hearing. (mchenrycountyil.gov)

Remember the risk. The Board of Review can confirm, reduce, or increase an assessment. File only when your comparables or record-error evidence support a lower number. (mchenrycountyil.gov)