Every non-farm property owner in Lake Forest and Lake Bluff will see their equalized assessed value rise about 4.3% under a tentative 2026 multiplier posted Monday, June 29, by the Lake County Chief County Assessment Officer.
The Shields Township multiplier jumped from 1.0379 (the 2025 final figure) to 1.0825 (tentative) for 2026. That 0.0446-point increase is the largest single-year change among all 18 Lake County townships.
What it means for your tax bill
The multiplier is applied to a property's assessed value before tax rates are layered on. For a Lake Forest home with a $200,000 assessed value, the new multiplier produces an equalized assessed value of $216,500, up from $207,580 under last year's figure. That $8,920 difference is then multiplied by the local tax rate to determine the additional tax owed. Actual bill impact depends on exemptions and final rates set by taxing bodies.
Why the multiplier rose
Illinois law requires that the three-year average of median assessment levels in each township equal 33.33% of market value. Shields Township's recent medians have been sliding: 33.15% (2023), 30.66% (2024), 28.69% (2025), producing a three-year average of 30.83%. The multiplier closes that gap.
Because 2026 is not a general reassessment year for Lake County, assessed values from 2023 are carried forward, according to the Lake County Board of Review's 2026 rules. The equalization multiplier is the primary mechanism adjusting those values to reflect current market conditions.
How to appeal
Property owners who believe their assessment is too high may file an appeal with the Lake County Board of Review, chaired by Nathan M. Herbst. All 2026 appeals must be submitted online through the county's Smartfile portal at lakecountyil.gov/smartfile. Shields Township appellants must use a comparable property grid from the township assessor's website.
The Board of Review's 2026 rules advise homeowners to first contact their township assessor's office, noting that "many times, the reason for the assessment can be made clear and the need for filing an appeal eliminated."
The specific filing deadline for Shields Township has not yet been posted. Residents can check boardofreview.lakecountyil.gov for the schedule. In 2025, Shields Township hearings ran from November 17 through December 16.
The multiplier remains tentative until finalized by the Board of Review. After that, the Illinois Department of Revenue performs a separate county-wide equalization that could adjust values further.
Separately, Lake County Treasurer Michael Zuren extended the second-half 2025 property tax due date (payable in 2026) to Tuesday, August 5, 2026.
