What if vacant land in Cook County was taxed more like commercial property?

Cook County assesses property by use. Homes and vacant land are assessed at 10% of their market value; commercial and industrial property at 25%. Because vacant land is assessed at the low residential rate, holding an empty lot is cheap — even on a busy commercial street. This page asks a narrow question: what if vacant land were assessed higher — to nudge owners to build rather than sit on it? Use the toggles to choose how high and how the money is handled:

Target 20% or 25%. 20% is partway to the commercial rate; 25% is the commercial / industrial maximum — the legal ceiling under Illinois' classification limit.
Revenue-neutral: each of Cook County's ~900 taxing bodies keeps its exact levy and re-strikes its rate over the slightly larger tax base, so vacant land's bill goes up and every other property's goes down by a small amount (the county collects the same total).
Not revenue-neutral: today's rates are left unchanged, so only vacant land pays more — every other property is untouched — and the county simply collects the extra (about $125 million more county-wide at 20%, or $188 million at 25%).

Results are grouped by assessment township; positive means the parcel pays more.

This is not a land value tax. Nothing here shifts tax off buildings and onto land, and there is no split rate or building abatement. The split-rate and abatement models elsewhere on this site are a different, larger reform. This page changes one thing only — the assessment ratio on vacant land — and leaves the rest of the property tax exactly as it is today.

Township

Assess vacant land at

Mode

Categories below use the assessor's standard property groupings, except that the reassessed vacant lots are pulled into their own “Vacant land (reassessed)” row so it matches the parcels actually being reassessed. Every other row is not reassessed: under “revenue-neutral” it sees a small decrease; under “not revenue-neutral” it is unchanged.

Category	Median % change	Median %	Median $	Net change ($)	Parcels

Exactly which parcels are reassessed. Only the x-00 vacant-land classes currently assessed below the 25% commercial rate — overwhelmingly class 1-00 “Vacant Land” (about 59,000 parcels), plus a few dozen 2-00/3-00/8-00 vacant codes. Those parcels — and only those — make up the “Vacant land (reassessed)” row in the table above, so the bar you see is exactly the set being reassessed. Two related classes are vacant land but are left untouched, and are broken out as their own rows so nothing is hidden: class 2-41 (“vacant land under common ownership with an adjacent residence” — homeowner side-lots), and the handful of 5-00 parcels already assessed at the 25% commercial rate. The reform only ever raises toward the target and never lowers.

Why class 1-90 is excluded. The assessor also has class 1-90, “Minor Improvement on Vacant Land” (about 2,600 parcels), which it files alongside vacant land. We looked at a sample across the county and found it is too mixed to reassess as one class: some are genuinely empty lots that arguably belong in 1-00; some are surface parking lots that belong in the commercial 5-90 class; and some are truly undevelopable — land under high-tension power lines or beneath the CTA “L” tracks — that correctly stays 1-90. Rather than double the assessment on all of them, we exclude 1-90 here and flag it as a class ripe for parcel-by-parcel reclassification.

Evidence: what happens when a vacant lot gets built on

Of the 60,361 Cook County parcels classed 1-00 “Vacant Land” in tax year 2023, 1,767 had a building by tax year 2024 (they moved to a residential, apartment or commercial class). Their combined assessed value rose from $25.0 million to $248.3 million (+893%), and their combined tax bills rose from $6.2 million to $60.4 million — about $54 million more billed in a single year, compared with when the same parcels were empty lots.

Became	Parcels	Assessed value, 2023	Assessed value, 2024	Change	Tax bills, 2023	Tax bills, 2024	Change
Residential (class 2)	1,482	$14.7M	$97.8M	+564%	$3.6M	$23.5M	+$19.9M
Apartments, 7+ units (class 3)	127	$4.1M	$58.7M	+1,319%	$0.9M	$12.9M	+$12.0M
Commercial / industrial (class 5)	158	$6.1M	$91.7M	+1,397%	$1.7M	$24.1M	+$22.4M
All redeveloped lots	1,767	$25.0M	$248.3M	+893%	$6.2M	$60.4M	+$54.2M

Method. Parcels are those classed 1-00 in tax year 2023 and in a class 2, 3 or 5 building class in tax year 2024. Assessed values are the Board of Review (final) values in both years; 1,766 parcels have one in both years. Tax bills are the billed amounts for tax years 2023 and 2024 (the 2024 bills were paid in 2025); 1,738 parcels have a bill on file for both years. The bill change also includes any change in tax rates between the two years, which is small next to a roughly tenfold jump in assessed value. Lots that went to an exempt or incentive class are not included. Sources: Cook County Assessor; Cook County Treasurer tax bills via Chicago Cityscape. Download the parcel-level data (CSV).