Cook County, Illinois · Property tax payment, PIN and assessment guide
Find a Cook County Tax Bill, Pay It Safely or Reach the Right Office
The office commonly called the “Cook County Tax Collector” is officially the Cook County Treasurer’s Office. It handles property-tax bills, payments, refunds, payment history, tax-sale searches and electronic billing.
Assessment value, exemptions, appeals and older redemption matters belong to different county offices. This guide explains the difference before you pay, mail a check, file an appeal or travel downtown.
Current bill-status warning: Tax Year 2025 First Installment was due April 1, 2026. As of the August 4, 2026 source review, the Treasurer’s official due-date page had not yet posted a Tax Year 2025 Second Installment due date. Do not estimate it from a prior year—use the date on the current official bill.
Official office
Cook County Treasurer.
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Find your county tax collector: Visit taxcollectors.org to find your county tax collector office, payment portal and deadlines. Paying online through your county portal is the fastest way to stop penalty accrual.
Office
118 N. Clark St., Room 112.
Hours
Monday–Friday, 9 a.m.–5 p.m.
Primary ID
14-digit Property Index Number.
Start with the right office
Which Cook County property-tax office handles your problem?
1
Treasurer
Pay bills, confirm posting, download tax bills, find refunds, check sold taxes and manage electronic billing.
2
Assessor
Search property details, review values and classifications, apply for homeowner or senior exemptions and file the first assessment appeal.
3
Board of Review
File a separate assessment appeal after the Assessor’s township work and appeal period reaches the Board.
4
County Clerk
Ask about prior-year forfeitures, open-item bills, certain tax-sale redemptions and local tax rates.
5
Township Assessor
Suburban property owners may get local help understanding property characteristics and assessment records.
6
Illinois PTAB
Review an eligible Board of Review decision through the state Property Tax Appeal Board process.
Choose the task you need to finish
The article is organized around real taxpayer actions, not repeated versions of “Cook County tax collector.”
Official payment workflow
How to search and pay Cook County property taxes online
Start at the Treasurer’s authorized systemThe Treasurer states that its online payment system is the only online system authorized and accepted by the office. Avoid ads, private payment services and old bookmarks.
Search by 14-digit PIN when possibleThe PIN identifies the parcel more reliably than an owner name. If you do not know it, use the official address search.
Confirm the property image and addressThe online process may show a property image. Compare the PIN, address, unit number, taxpayer and township before continuing.
Select the correct tax year and installmentDo not confuse Tax Year 2025 First Installment with an older Second Installment, omitted assessment or delinquent balance.
Check exemption and refund indicatorsThe Property Tax Overview can show exemptions, available refunds and whether delinquent taxes have been sold. Review these before making a duplicate payment.
Choose ACH or card intentionallyACH from a checking or savings account is listed as no fee. Card payment carries a third-party fee.
Save proof and confirm postingKeep the confirmation, PIN, tax year, installment, amount and bank record until Payment Status shows the payment correctly.
Find and verify the 14-digit Property Index Number
The Property Index Number, or PIN, is Cook County’s parcel identifier. It is printed on property-tax bills, closing documents, deeds and Assessor notices.
Tax bill
Use the PIN printed on the payment coupon and bill details. Keep the hyphenated format when copying it.
Closing or deed
Recent buyers can check the settlement file or recorded deed, but should still verify the property in current county records.
Address search
Use the Treasurer for tax-bill records or the Assessor for property characteristics and assessed value.
Condo and multi-unit warning: Similar street addresses can have different PINs. Match the unit number and property details rather than paying the first address result.
What the Cook County Property Tax Overview can tell you
Use each field for a specific decision
Tool or field
What it shows
Next action
Property and PIN
Parcel identity, address and associated tax record.
Confirm the exact parcel before paying or mailing.
Bill copy
Downloadable tax bill and payment coupon.
Use the correct installment coupon for mail or bank payment.
Payment status
Whether a payment has posted to the selected PIN and installment.
Keep your receipt until posting is verified.
Refund search
Potential duplicate or overpayment refund connected with the property.
Review eligibility and file the correct refund form.
Exemption history
Exemptions reflected in property-tax information.
Use the Assessor when an exemption is missing or incorrect.
Sold-tax search
Whether delinquent taxes have been sold at a tax sale.
Stop normal-payment assumptions and follow redemption guidance.
20-year tax history
Long-term bill history and changes.
Use for comparison, not as a substitute for the current amount due.
Taxing-district debt
Debt and pension information attributed to local taxing districts.
Use for understanding the bill, not for changing the assessed value.
Cost and convenience
Cook County property-tax payment methods and fees
Current Treasurer payment routes
Method
Published fee or rule
Best use
Important limitation
Online bank account
No fee for ACH debit from checking or savings.
Lowest-cost remote payment.
Taxpayer is responsible for correct bank information.
Online card
2.10% third-party processing fee.
Card convenience when the fee is acceptable.
Electronic service charges are nonrefundable.
Chase Bank
No separate Treasurer fee listed.
Current or eligible delinquent bill with proper coupon.
Open-item, forfeiture-redemption and tax-sale-redemption bills are not accepted.
Community bank
Direct debit through a participating bank.
Taxpayer has an account at that bank.
Some back-tax and special bill types are excluded.
Mail
Postage and bank check costs.
One check and coupon per PIN when timing permits.
USPS postmark rules matter near deadlines.
Treasurer office
Depends on payment method.
Complex prior-year, refund, posting or redemption issue.
Weekday hours, downtown travel and security screening.
10 or more PINs online
Potential $2 enhanced processing fee per PIN and installment.
Entities making high-volume payments.
The fee is determined and billed under county ordinance.
Delinquent-payment rule: The Treasurer directs taxpayers with delinquent taxes to make only one online payment per day so late fees post correctly.
Mail and authorized bank payments
Rules that prevent a Cook County tax payment from being rejected
Tax Year 2025 mailing addressCook County Treasurer PO Box 805438 Chicago, IL 60680-4116
Use the address on the current bill if a later installment publishes a different remittance instruction.
Check details
14-digit PIN
Taxpayer name
Property location and unit
Mailing address
Phone and email
Tax year and installment
Use one envelope per PINSubmit one tax-bill coupon and one check for each PIN. Multiple properties require separate checks and coupons.
Write the PIN on the envelopeThis helps the Treasurer identify the property if the envelope and payment materials become separated.
Request a manual USPS postmark near the deadlineThe Treasurer recommends taking the envelope to a Postal Service retail counter for a local postmark.
Do not rely on a private-carrier shipment dateFedEx and UPS payments are treated as paid when received, not when shipped.
Keep the upper bill portionMail the payment coupon, not the entire record copy, and keep a copy of the check and coupon.
Verify after the check clearsA canceled check is a receipt, but the taxpayer should still confirm correct posting to the PIN and installment.
Chase coupon requirement: Bring the correct original or duplicate payment coupon. A general property-information printout may not be accepted as a payment coupon.
2025 First Installment due April 1, 2026The Treasurer mailed nearly 1.8 million first-installment bills. The first installment equals 55% of the prior year’s total tax.
Second Installment date not yet listed at source reviewAs of August 4, 2026, the official due-date page did not show a Tax Year 2025 Second Installment due date.
Exemptions are applied to the Second InstallmentThis is why the first installment can look different from the final annual total and why missing-exemption review matters before the second bill.
Do not publish or calculate an estimated Second Installment deadline. Cook County dates have changed in prior cycles. Use the date on the official bill or Treasurer due-date page.
Late interest, partial payments and the Payment Plan Calculator
For standard delinquent property taxes, Cook County currently describes state-mandated interest at 0.75% per month, or 9% per year. Use the official system for the amount due on the actual payment date.
Who can use the calculator
Taxpayers with a delinquent balance of $100 or more can create a monthly or twice-monthly planning schedule.
One plan per tax year
A plan for one delinquent year does not enroll a different tax year or current bill.
Not legal protection
Using the tool or making some partial payments does not remove the property from Annual Tax Sale risk.
Search the PIN and open the delinquent billThe calculator appears for qualifying unpaid balances.
Choose monthly or twice-monthly paymentsCompare the recommended schedule against income and other property-tax installments.
Print or download the planKeep the schedule and sign up for available email or text reminders.
Pay every required balance before the saleThe unpaid total must be paid in full before the Annual Tax Sale begins for that tax year.
Keep current taxes separateA delinquent-year plan does not satisfy the next current-year installment.
Interest exceptions: Omitted assessments and special bill types can follow different statutory interest rules. Use the amount printed on that specific official bill rather than applying the standard 0.75% rate yourself.
Email-address answer: The Treasurer does not publish a general taxpayer-service email address as the main contact route. Use the official Contact Us by Email form. Media addresses shown elsewhere on the website are not the correct route for a property-tax account question.
Written-response timing: The phone page says real-estate professionals must submit requests through the email form and that many written requests are answered within three business days, while complex requests may take five to seven business days.
Search assessed value, property details and exemption history
Search by PIN
Enter the 14-digit PIN to view estimated market value, assessed value, property characteristics, exemption status, appeal history and Certificate of Error history.
Search by address
Enter house number, direction, unit, street name and city. The Assessor instructs users not to include designations such as Avenue, Street, Place or Lane.
Assessor values are not the same as the tax amount
Item
Meaning
Common mistake
Estimated market value
Assessor’s estimate of current market worth.
Treating it as the amount owed.
Assessed value
Value used in the property-tax calculation before equalization and exemptions.
Assuming the assessed value equals the final bill.
Residential assessment
Generally 10% of estimated market value.
Applying the residential percentage to commercial property.
Commercial assessment
Generally 25% of estimated market value.
Comparing it directly with a residential ratio.
Exemption history
Shows exemption status reflected in Assessor records.
Assuming the Treasurer can add a missing exemption.
Property location
Assessor’s location reference for the parcel.
Treating it as a guaranteed legal or postal address.
Cook County reassesses property on a triennial cycle. In 2026, the south and west suburbs undergo reassessment. North-suburban and City of Chicago properties are not generally reassessed in 2026, but property owners can still appeal when their township opens.
Identify the townshipAppeal dates are based on township, not only municipality or postal city.
Check the Assessor calendarThe opening date and last filing date can change as notices and assessment rolls are issued.
File the Assessor appeal first when availableReview the 2026 rules, property characteristics, comparables and supporting documents.
Track the Board of Review window separatelyThe Board is independent from the Assessor and offers another appeal opportunity after the township reaches its Board filing period.
Do not use an exemption filing as an assessment appealHomestead exemptions and Certificates of Error use separate Assessor processes.
Time-sensitive examples at the August 4, 2026 review: The Assessor calendar showed Elk Grove closing August 4, Stickney August 12, West Chicago August 21 and Northfield September 4. These windows change quickly; use the live calendar for your township.
Two appeal stages: The Cook County Assessor sets the initial taxable value. The Board of Review is a separate quasi-judicial office that can review that assessment later in the cycle.
The Assessor lists homeowner, senior, Senior Freeze, disability, veteran, returning-veteran, longtime-homeowner and home-improvement exemptions. Exemptions reduce equalized assessed value; the reduction is not the same as a dollar-for-dollar reduction shown in the exemption amount.
Homeowner Exemption
For eligible owners who occupy the property as their principal residence. Once applied, it generally auto-renews.
Senior Exemption
For qualifying owners age 65 or older who own and occupy the property as their principal residence.
Senior Freeze
Requires annual filing and income eligibility. The Assessor’s current page lists a $65,000 household-income limit using the specified calendar year.
May 15, 2026 filing status: The Assessor says applications received after May 15, 2026 are processed as Certificates of Error. Approved savings may appear on the Second Installment or an adjusted bill.
Prior-year recovery: A Certificate of Error may allow eligible owners to recover missing exemption savings from prior years. Search the exact exemption page for the years currently open.
Search for an overpayment before sending another payment
The Treasurer’s 2026 site advertises searches covering approximately $105 million in available property-tax refunds and $19 million in missing senior exemptions going back four years.
Owner and mortgage company both paidSearch for a duplicate-payment refund before assuming the extra payment was automatically returned.
Two lenders or title companies paidCollect both payment records and closing documents to establish who is entitled to the refund.
Assessor approved a Certificate of ErrorThe Assessor corrects the exemption or value; the Treasurer handles refund timing and payment processing.
PTAB decision reduced the taxUse the Treasurer’s separate Property Tax Appeal Board refund process.
Mortgage escrow appears unpaidAsk the servicer for the date, amount, PIN and confirmation before paying again.
Property was sold years agoA prior owner may still be entitled to a duplicate-payment refund connected with the period they owned the property.
Correct PIN and tax year
Both payment dates and amounts
Canceled checks or confirmations
Mortgage or title-company documentation
Closing statement when ownership changed
Certificate of Error or PTAB decision when applicable
This is no longer a normal payment situation. When taxes have been sold, legal deadlines, redemption costs and payment instructions can differ from an ordinary delinquent bill.
Search sold-tax status by PINUse the Treasurer’s property overview before trusting a solicitation or third-party letter.
Contact the correct redemption officeThe Treasurer’s phone directory directs certain prior-year forfeiture, open-item and tax-sale-redemption questions to the Cook County Clerk at 312-603-5656.
Obtain the official redemption amountDo not calculate it from principal tax and ordinary monthly interest alone.
Use the required bill and payment routeOpen-item, forfeiture-redemption and tax-sale-redemption bills cannot be paid at Chase and may require mail or Treasurer-office handling.
Get legal advice when the consequences are seriousThe Treasurer explicitly states that it cannot give legal advice about tax sales, redemption under protest or sale-in-error options.
Common Cook County tax problems and the fastest next step
Address search shows no propertyRemove Street, Avenue, Place, Lane or abbreviations in the Assessor search. Try the PIN from the bill or closing file.
Wrong condo unit appearsStop and match the 14-digit PIN, unit and property image. Never pay from street address alone in a multi-unit building.
Payment cleared but status is unpaidGather the canceled check or confirmation, PIN, installment and payment date, then contact the Treasurer before paying again.
Bill is high because an exemption is missingPaying the Treasurer will not add the exemption. File with the Assessor and use the Certificate of Error route when applicable.
Taxpayer name or mailing address is wrongUse the Treasurer’s name/address update service for the tax bill and check whether Assessor or recorded-property records also require correction.
Mortgage company says it paidRequest proof tied to the same PIN, tax year and installment. Check the official payment status rather than relying on an escrow statement alone.
One installment is paid but another remainsOpen every year and installment in the property overview. Do not assume a zero balance on one item clears the entire PIN.
Second Installment is not availableDo not send an estimated amount. Sign up for eBilling or recheck the official due-date and property overview pages.
Delinquent payment is split into several transfersThe Treasurer says to make only one online delinquent payment per day so late fees post correctly.
Office email is requestedUse the official taxpayer email form. Do not send account information to media-relations email addresses.
Useful Treasurer contact message“I am asking about PIN [14-digit PIN], Tax Year [year], [first/second] installment. The issue is [missing payment / refund / incorrect bill / delinquent balance]. The payment date and confirmation or check number are [details]. Please confirm the current status and correct next step.”
Before paying
Final Cook County payment-verification checklist
14-digit PIN matches
Property address and unit match
Tax year and installment are correct
Mortgage escrow was checked
Refund and duplicate-payment status were reviewed
Exemption issue was routed to Assessor
Processor fee is visible
Confirmation will be saved
Official action links
Cook County sources to use when you are ready to act
Source review: August 4, 2026. The guide uses current Treasurer, Assessor and Board of Review information. Due dates, appeal windows, payment fees, refund totals, sold-tax status, office closures and mailing instructions can change. The official bill and responsible county office control.
Internal Illinois guide
Another Illinois county tax guide
The uploaded site URL list included one clearly relevant Illinois county page. Use it only when the property belongs to Lake County rather than Cook County.
L
Lake County, Illinois
Use the Lake County guide for a Lake County property-tax payment, office or assessment question.
What is the official Cook County IL Tax Collector website?
Cook County property-tax collection is handled by the Cook County Treasurer’s Office. Use cookcountytreasurer.com and its Property Tax Overview to search by 14-digit PIN or address, pay taxes, download bills, check refunds and review payment status.
How do I search a Cook County property-tax bill?
Use the Treasurer’s Property Tax Overview and search by 14-digit Property Index Number or property address. Verify the PIN, address, unit, tax year and installment before paying.
What is the Cook County Treasurer phone number and address?
The Treasurer’s taxpayer-service phone number is 312-443-5100. The office is at 118 North Clark Street, Room 112, Chicago, Illinois 60602.
What is the Cook County Treasurer email address?
The Treasurer directs taxpayer account questions through its official Contact Us by Email form rather than publishing one general taxpayer-service email address. Do not use media-relations email addresses for a property-tax account issue.
What are the Cook County Treasurer office hours?
The official hours are Monday through Friday from 9:00 a.m. to 5:00 p.m. The office is closed Saturday, Sunday and designated county holidays.
When is the Cook County 2025 Second Installment due in 2026?
As of August 4, 2026, the Treasurer’s official due-date page had not posted the Tax Year 2025 Second Installment due date. Use the date on the official bill and do not estimate it from a previous year.
Is it free to pay Cook County property taxes online?
Yes. The Treasurer lists no fee for ACH debit from a checking or savings account through its authorized system. Credit and debit card payments carry a 2.10% third-party processing fee.
What is the difference between the Cook County Treasurer and Assessor?
The Treasurer handles bills, payments, payment status, refunds and tax-sale searches. The Assessor handles assessed value, property characteristics, classifications, exemptions and the first assessment-appeal opportunity.
How do I search Cook County Assessor property records?
Search by 14-digit PIN or address on the Assessor website. For address searches, enter the street name without designations such as Street, Avenue, Place or Lane.
What should I do if my Cook County taxes are delinquent?
Search the current balance, use only one online delinquent payment per day, and consider the Treasurer’s Payment Plan Calculator if the balance is at least $100. Interest generally accrues at 0.75% per month, and the balance must be paid in full before the Annual Tax Sale to avoid sale.