Stephenson County uses a publication-triggered complaint calendar rather than a single safely reusable annual date. The posted Board rules say a complete complaint is due September 10 or 30 calendar days after the current assessment list is published. As of the July 29 review, the county assessment page still displayed 2025 change lists and did not establish the controlling 2026 township deadline. Owners should monitor the official page and confirm the date with the Board clerk. The $249 FairPath owner-guided evidence packet is available now for Stephenson County properties and can organize the parcel record, owner corrections, recent sales, equity comparisons, photographs, and Board rules. FairPath does not file the complaint, appear at the hearing, or turn an unconfirmed publication date into a filing promise.
Assessment context: Stephenson's process begins with the township assessor or Chief County Assessment Officer, not the Treasurer's tax-bill office. The county directs Freeport Township parcels, whose PIN begins with 18, to the Freeport Township Assessor and lists other local assessment officials separately. Illinois generally assesses non-farm property at one-third of fair cash value as of January 1, subject to equalization. Review the online property record for the PIN, land and improvement values, property class, building characteristics, exemptions, and recent assessment changes. Then separate possible grounds: a recent arm's-length sale, overvaluation shown by comparable sales or appraisal, unequal treatment relative to similar property, a physical-data discrepancy, or a legal or preferential-assessment issue. A higher tax bill, a tax-rate change, or the percentage increase alone is not a valuation ground before the Board.
Filing process: First discuss the record with the responsible township assessor or Chief County Assessment Officer, but do not let that discussion consume the statutory complaint period; the Board rules say the deadline cannot be extended. For a residential parcel, use the county's BOR-R-1 form and follow the current rules for signatures, PINs, requested assessment, selected grounds, copies, and evidence. The posted rules reject faxed and emailed complaints. Hand-delivered material is filed when received. United States mail can use the official cancellation mark, but metered mail arriving late also needs a United States Postal Service date stamp; private carriers do not receive that postmark treatment. The Board requires all contiguous parcels with common ownership and use to be included and permits one form plus an addendum for a qualifying multi-PIN property. An incomplete filing can be returned and must still be corrected before the deadline.
Evidence to review: Submit the evidence with the complaint because Stephenson's rules generally require the owner's full evidence packet at filing. A documented appraisal may arrive up to 15 calendar days after the filing deadline, but the Board treats other late evidence differently. For overvaluation, identify recent similar nearby sales and show sale date, price, PIN, property record, exterior area, lot, age, style, condition, and adjustments. For equity, compare assessment treatment among genuinely similar neighborhood properties rather than substituting market sales for an assessment-uniformity claim. For a physical-data discrepancy, provide clear color photographs, measurements, permits, inspection material, or other records that establish the error. The rules require disclosure of a recent subject sale and, for recent construction, construction costs and permits. They also call for two copies of documents other than the complaint and impose extra-copy obligations when the requested assessed-value reduction is at least $50,000.
Current deadline guidance: 2026 date pending publication: September 10 or 30 days after the assessment list. Stephenson County's posted Board rules require a fully completed complaint by September 10 or within 30 calendar days after publication of the current-year assessment list. The county had not posted a 2026 township assessment-list deadline on the reviewed page as of July 29, so owners must confirm the 2026 publication and controlling date with the Board clerk before filing.
Stephenson's deadline is tied to assessment-list publication: September 10 or 30 calendar days after the current list. The official page must be checked for the 2026 township publication before choosing a date.
Freeport Township parcels are identified by PINs beginning with 18 and are directed to the Freeport Township Assessor, while the county office supports the remaining township assessment structure.
The Board rejects faxed and emailed complaints and distinguishes an official United States Postal Service postmark from private-carrier delivery or unsupported metered mail.
Stephenson generally requires evidence with the original complaint, two copies of supporting documents, recent-sale disclosure, and additional copies for a requested assessed-value reduction of at least $50,000.
Official filing authority: Stephenson County Board of Review. https://stephensoncountyil.gov/departments/county_assessment_office/forms___publications/index.php
Source: Stephenson County, Illinois, County Assessment Office, https://stephensoncountyil.gov/departments/county_assessment_office/index.php. Reviewed 2026-07-29.
Source: Stephenson County, Illinois, Board of Review, https://stephensoncountyil.gov/departments/county_assessment_office/board_of_review/index.php. Reviewed 2026-07-29.
Source: Stephenson County Board of Review, 2025 Stephenson County Board of Review Rules, https://stephensoncountyil.gov/Document_Center/Department/County%20Assessment%20Office/2025%20Stephenson%20County%20Board%20of%20Review%20Rules.pdf. Reviewed 2026-07-29.
Source: Stephenson County Chief County Assessment Office, Assessment Complaint Forms and Publications, https://stephensoncountyil.gov/departments/county_assessment_office/forms___publications/index.php. Reviewed 2026-07-29.
Source: Illinois Department of Revenue, Assessment Appeals, https://tax.illinois.gov/localgovernments/property/appeals.html. Reviewed 2026-07-29.