What the county's own roll says, and how many parcels sit above their neighbours.
111,043parcels on record
452with a published assessment
$96,516median assessed value
48above their neighbourhood median
Among those, the typical excess is $7,286 of
assessed value above the median for like-classified land in the same town — $349,725
in total across Mchenry County.
A median has half of everything above it by definition, boards do not grant every
uniformity claim, and being above a median is a ground to argue rather than proof of error. These
are assessed values, not tax bills.
Your deadline in Mchenry County
30 days from the publication of your township's assessment roll in the local newspaper. The window is short and it is not the same date across the county.
Statutory basis: 35 ILCS 200/16-55.
A late filing cannot be cured, so confirm the date on your own notice — it is not the same across the county.
How the assessment was calculated
Illinois assesses at 33.33% of market value.
The assessor estimates market value by mass appraisal — a model over recent sales, adjusted by the
characteristics they hold on file for your property. If those characteristics are wrong, the number
is wrong. The full anatomy is here.
The argument most people miss
Beyond “my house is worth less than they say”, the Illinois Constitution requires uniform
taxation. If comparable property near you is assessed at a lower rate per square foot, that is a
ground for relief in its own right — no appraisal needed, and built from figures the assessor
published themselves.