How much did assessments move around me, and where does mine sit?
Your assessment notice gives you two numbers — your new value and your old one — and tells you nothing about the homes around you. This page computes the rest. Type your address or your 14-digit PIN and it works out your own change from the Assessor’s mailed values, then puts it beside the whole distribution for your assessment neighborhood and your township: the median change, the range the middle half of homes fall in, and how many homes are behind each figure. In the 11 townships reassessed so far for 2026 the median home moved between +8.3% and +26.0%, across 182,295 homes — and inside a single township the neighborhoods ranged from −9.1% to +45.7%.
Cook County townships reassessed for 2026, ranked by median change
Cook County reassesses one region a year and mails township by township over months. These 11 townships have 2026 mailed values whose median change is at least 2% away from flat — that is what makes a year a reassessment for a township rather than a year the value simply carried forward. “Middle half of homes” is the 25th to the 75th percentile of the change: half of the homes compared fall inside that range, and half fall outside it.
| Township | Median change, 2025 to 2026 | Middle half of homes | Homes compared | Neighborhoods reassessed |
|---|---|---|---|---|
| Lemont | +26.0% | +18.4% to +35.5% | 8,604 | 12 |
| River Forest | +25.8% | +16.8% to +36.7% | 4,239 | 5 |
| Lyons | +24.7% | +16.3% to +33.7% | 38,150 | 33 |
| Berwyn | +23.7% | +14.3% to +32.3% | 14,104 | 7 |
| Palos | +23.3% | +14.5% to +30.3% | 20,470 | 23 |
| Oak Park | +22.9% | +14.7% to +30.3% | 17,014 | 11 |
| Riverside | +21.4% | +12.9% to +32.1% | 5,896 | 6 |
| Stickney | +20.0% | +14.2% to +28.0% | 13,163 | 7 |
| Cicero | +19.6% | +12.5% to +28.0% | 14,511 | 11 |
| Bremen | +19.2% | +10.3% to +26.7% | 40,880 | 37 |
| Calumet | +8.3% | +0.0% to +20.0% | 5,264 | 2 |
Twelve further townships — Barrington, Elk Grove, Evanston, Hyde Park, Lake View, Leyden, Maine, New Trier, Northfield, Norwood Park, Rogers Park and West Chicago — have 2026 mailed values whose median change is 0.0%: they were not reassessed this year, and the tool shows their last reassessment instead. The remaining 15 of Cook County’s 38 townships had no 2026 mailed values at all when we loaded the file on 13 September 2026.
The neighborhoods that moved most and least in the 2026 reassessment
The Assessor divides each township into assessment neighborhoods and values them separately, which is why one township can hold both ends of this list. Bremen Township’s neighborhoods ran from −9.1% to +33.3% in the same mailing. These are the 12 largest and 12 smallest median changes among the 154 neighborhoods reassessed for 2026 across those 11 townships. The Assessor identifies neighborhoods by a five-digit code, not a name, so that is what we print.
| Township · neighborhood | Median change | Middle half of homes | Homes compared | Median assessed value 2026 |
|---|---|---|---|---|
| Lemont · 19040 | +45.7% | +37.5% to +55.8% | 330 | $95,850 |
| Lyons · 21062 | +39.7% | +29.8% to +40.2% | 962 | $101,001 |
| Lyons · 21165 | +37.8% | +30.8% to +45.8% | 483 | $57,000 |
| River Forest · 33050 | +34.8% | +26.2% to +45.6% | 454 | $128,001 |
| River Forest · 33020 | +34.6% | +24.4% to +47.1% | 600 | $95,001 |
| Berwyn · 11040 | +33.3% | +26.1% to +40.9% | 1,739 | $33,000 |
| Lyons · 21061 | +33.3% | +25.1% to +46.1% | 407 | $152,000 |
| Bremen · 13400 | +33.3% | +20.5% to +62.2% | 75 | $21,000 |
| Riverside · 34050 | +33.3% | +26.7% to +42.3% | 740 | $70,000 |
| Lyons · 21013 | +33.2% | +24.4% to +42.1% | 925 | $76,000 |
| River Forest · 33030 | +32.2% | +24.4% to +37.2% | 891 | $75,000 |
| Lyons · 21067 | +32.0% | +27.0% to +40.1% | 413 | $94,001 |
| Township · neighborhood | Median change | Middle half of homes | Homes compared | Median assessed value 2026 |
|---|---|---|---|---|
| Bremen · 13270 | +9.5% | +5.3% to +17.6% | 953 | $21,001 |
| Bremen · 13110 | +7.4% | +5.3% to +10.1% | 709 | $3,606 |
| Bremen · 13344 | +6.9% | +4.3% to +10.8% | 113 | $31,000 |
| Bremen · 13330 | +6.7% | +0.0% to +11.1% | 137 | $17,000 |
| Palos · 30100 | +0.7% | −9.4% to +9.9% | 38 | $162,849 |
| Bremen · 13120 | +0.0% | −9.3% to +10.5% | 2,200 | $10,000 |
| Calumet · 14030 | +0.0% | −5.9% to +15.3% | 2,340 | $13,000 |
| Calumet · 14040 | +0.0% | −14.3% to +5.9% | 560 | $3,827 |
| Bremen · 13010 | −1.3% | −20.0% to +15.0% | 1,765 | $8,000 |
| Bremen · 13340 | −8.3% | −16.8% to +0.0% | 286 | $11,000 |
| Bremen · 13320 | −9.1% | −14.3% to +0.0% | 808 | $10,000 |
| Bremen · 13020 | −9.1% | −17.6% to −5.9% | 540 | $7,000 |
Every figure compares each class-2 residential parcel’s 2026 mailed total with its own 2025 mailed total, counting only parcels that carry a mailed value in both years and are still in the same neighborhood. We publish no median, range or value for a neighborhood-year with fewer than 30 homes compared: 28 of the 2,106 neighborhood-years we hold fall below that floor and carry a count only. The median assessed value is an assessed value, not a market value — in Cook County a home’s assessed value is roughly 10% of what the Assessor estimates it is worth.
Three things this page is careful not to claim
An assessment is not a tax bill. Your bill is your assessment after exemptions, multiplied by a rate the taxing bodies set from their levies — and that rate falls when assessments across the district rise. A 25% assessment increase does not make a 25% bill. Nothing on this page predicts what you will pay.
A median is not a prediction for one home. Half the homes in your neighborhood moved more than the median and half moved less, which is why we print the 25th-to-75th-percentile range beside it and the number of homes behind both. Your own change is your own.
Moving with your neighborhood is normally a weak appeal argument. An appeal argues that your value is wrong relative to comparable homes, not that it went up. If your increase sits inside the middle half of your neighborhood, that is the Assessor doing to you what it did to your neighbors, and a hearing officer will read it that way.
A comparison, not a change
The free Assessment Check is the one that matters for an appeal: it compares your home with near-identical homes nearby — same neighborhood, similar size and age — and tells you free whether yours is assessed above them, which is the argument an appeal is actually made of. This page and that one answer different questions, and the difference is the point.
Where the check finds a case and your township’s window is open, the Tax Appeal Evidence Packet documents that comparison as evidence you file yourself, for $59. We don’t file anything for anyone, we aren’t your lawyer or your tax representative, and appealing at either office is free.
Check whether your appeal window is still open · all 38 townships compared · how we compute these figures
About neighborhood assessment changes
How much did assessments go up in Cook County for 2026?
It depends entirely on where you are. Among the 11 townships reassessed so far for 2026, the median home moved between +8.3% in Calumet and +26.0% in Lemont, across 182,295 homes compared. Within them, the 154 reassessed neighborhoods ran from −9.1% (Bremen 13020) to +45.7% (Lemont 19040). There is no single county figure worth quoting, which is why this page makes you look up your own.
What is an “assessment neighborhood”, and how do I find mine?
The Cook County Assessor divides each township into assessment neighborhoods and values them separately; the office identifies them by a five-digit code rather than a name, so that is what we show. Enter your address or 14-digit PIN above and the tool reads the neighborhood code straight off your parcel record, then shows that neighborhood’s whole distribution.
My assessment went up 25%. Will my tax bill go up 25%?
No, and the two are not proportional. The bill is your assessment after exemptions multiplied by a rate that the taxing bodies set from their levies, and that rate goes down when assessments across the district go up. This page computes assessment changes only and says nothing about rates, exemptions or bills.
Is a big increase on its own a good reason to appeal?
Not by itself. An appeal argues your value is wrong compared with near-identical homes, not that it rose. If your change sits inside the middle half of your neighborhood — the 25th-to-75th-percentile range this page prints — you moved with your neighbors, which is normally a weak argument. The free Assessment Check measures the thing that does matter: whether your home is assessed above comparable homes.
Why does my neighborhood show no figures?
Either too few homes, or no second year. We publish no median or range for a neighborhood-year with fewer than 30 homes carrying a mailed value in both years — 28 of the 2,106 neighborhood-years we hold are below that floor, and we show the count rather than a spread. And 15 of Cook County’s 38 townships had no 2026 mailed values at all in the file we loaded on 13 September 2026, so their latest reassessment is 2024 or 2025.
Where do these numbers come from, and is anything I type sent to you?
From the Cook County Assessor’s Assessed Values (uzyt-m557) and Parcel Universe (pabr-t5kh) open datasets, loaded 13 September 2026, covering tax years 2023 to 2026. Nothing you type is sent anywhere: the address is matched in your browser against files this site publishes, and the neighborhood figures are pre-computed static files.
The other free tools
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