The Cook County Property Tax Reassessment Cycle: A Complete Township-by-Triad Map
Every property in Cook County is reassessed on a three-year rotation called the Cook County reassessment cycle. The county's 30+ townships are divided into three triads — City of Chicago, North/Northwest Suburbs, and South/Southwest Suburbs — and one triad is reassessed each year. Knowing which triad your township belongs to tells you exactly when your property will be reassessed and when your best appeal opportunity arrives.
Below is the complete township-by-triad reference map, including the next three reassessment years for each group.
City of Chicago Triad
Reassessment years: 2025 (most recent), 2028, 2031
The City of Chicago triad was reassessed in 2025. Their next reassessment is in 2028, but property owners can still file appeals every year with the Assessor and Board of Review.
| Township | Most Recent Reassessment | Next Reassessment |
|---|---|---|
| Hyde Park | 2025 | 2028 |
| Jefferson | 2025 | 2028 |
| Lake | 2025 | 2028 |
| Lake View | 2025 | 2028 |
| North Chicago | 2025 | 2028 |
| Norwood Park | 2025 | 2028 |
| Rogers Park | 2025 | 2028 |
| South Chicago | 2025 | 2028 |
| West Chicago | 2025 | 2028 |
North/Northwest Suburban Triad
Reassessment years: 2024 (most recent), 2027, 2030
The north and northwest suburban townships were last reassessed in 2024. Their next reassessment is in 2027, but property owners can still file appeals every year with the Assessor and Board of Review.
| Township | Most Recent Reassessment | Next Reassessment |
|---|---|---|
| Barrington | 2024 | 2027 |
| Elk Grove | 2024 | 2027 |
| Evanston | 2024 | 2027 |
| Hanover | 2024 | 2027 |
| Leyden | 2024 | 2027 |
| Maine | 2024 | 2027 |
| New Trier | 2024 | 2027 |
| Niles | 2024 | 2027 |
| Northfield | 2024 | 2027 |
| Palatine | 2024 | 2027 |
| Schaumburg | 2024 | 2027 |
| Wheeling | 2024 | 2027 |
South/Southwest Suburban Triad
Reassessment years: 2026 (current), 2029, 2032
The south and southwest suburban townships are being reassessed right now in 2026. If your property is in any of these townships, the Assessor is updating your assessed value this year.
| Township | Current Reassessment | Next Reassessment |
|---|---|---|
| Berwyn | 2026 | 2029 |
| Bloom | 2026 | 2029 |
| Bremen | 2026 | 2029 |
| Calumet | 2026 | 2029 |
| Cicero | 2026 | 2029 |
| Lemont | 2026 | 2029 |
| Lyons | 2026 | 2029 |
| Oak Park | 2026 | 2029 |
| Orland | 2026 | 2029 |
| Palos | 2026 | 2029 |
| Proviso | 2026 | 2029 |
| Rich | 2026 | 2029 |
| River Forest | 2026 | 2029 |
| Riverside | 2026 | 2029 |
| Stickney | 2026 | 2029 |
| Thornton | 2026 | 2029 |
| Worth | 2026 | 2029 |
How to Read These Tables
Township is the Cook County township where your property is located. You can find your township on your property tax bill or by searching your PIN on the Cook County Assessor's website.
Most Recent / Current Reassessment is the last year the Assessor updated property values for that township. This is when the Assessor reviewed market data and published new proposed assessments.
Next Reassessment is the next time your township's properties will be fully re-evaluated. In between reassessment years, your assessed value generally stays the same (though you can still appeal it).
Which Triad Is Being Reassessed in 2026?
The south and southwest suburban triad is being reassessed in 2026. This includes the seventeen townships listed in the third table above: Berwyn, Bloom, Bremen, Calumet, Cicero, Lemont, Lyons, Oak Park, Orland, Palos, Proviso, Rich, River Forest, Riverside, Stickney, Thornton, and Worth.
If you own commercial property in any of these townships, this is your highest-impact year to file an appeal. The assessed value set during the 2026 reassessment becomes your base for the next three years. Check the 2026 appeal deadlines to make sure you don't miss your township's filing window.
Can You Appeal in Non-Reassessment Years?
Yes. Even if your township isn't being reassessed, you can file an appeal with the Assessor's Office and the Board of Review every year. However, reassessment years offer the best opportunity for significant reductions because the Assessor is actively recalculating values based on current market data.
For a deeper explanation of the triennial cycle and why reassessment years matter most, see our guide on when Cook County reassesses property taxes.
How TaxRival Can Help
TaxRival monitors the reassessment cycle and files appeals at the optimal time for your property. Whether your township is in a reassessment year or not, we analyze your assessment, build evidence-based cases, and handle every step of the appeal process. Our 25% contingency fee means you pay nothing unless we reduce your assessment. Look up your property to get started.
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