Cook County property taxes are billed in two installments, and both pay off the previous year’s tax liability. For Tax Year 2025, the first installment is due April 1, 2026, pushed back from the usual March 1 because the prior cycle ran late.1Cook County Treasurer’s Office. Important Dates The second installment due date for Tax Year 2025 has not been announced; it depends on when assessments and appeals are finalized. Miss either date and interest starts accruing the next day.
The First Installment
The first installment is fixed by Illinois law at 55 percent of your previous year’s total tax.2Illinois General Assembly. Illinois Code 35 Revenue 200/21-30 Think of it as a placeholder payment while the county finishes calculating what you actually owe for the year.
Normally this bill is due March 1. For Tax Year 2025 (payable in 2026), the Treasurer extended the deadline to April 1, 2026 because the Tax Year 2024 second installment ran behind schedule.1Cook County Treasurer’s Office. Important Dates The whole system runs in arrears, meaning the bill arriving in your mailbox in 2026 covers 2025, not the current year.3Cook County Treasurer’s Office. Why We Pay Property Taxes In Arrears
The Second Installment
The second installment covers the balance after your actual assessed value and local tax rates are applied. The due date floats because it depends on how fast the Cook County Assessor’s Office and the Board of Review process appeals and certify rates. When everything stays on track, this bill typically comes due around August 1.
Lately, “on track” has been the exception. The Tax Year 2024 second installment bills weren’t released until mid-November 2025 and weren’t due until December 15, 2025.4Cook County Government. Cook County Second Installment Property Tax Bills Expected to be Released by November 14, Due December 15 As of early 2026, the Tax Year 2025 second installment date has not been set. Check cookcountytreasurer.com for the announcement.
What Happens If You Pay Late
Interest starts accruing the day after a missed deadline at 0.75 percent per month on the unpaid balance. Any portion of a month counts as a full month. This rate applies to Tax Year 2023 and all tax years after it; delinquent taxes from before 2023 carry the older 1.5 percent monthly rate.5Illinois General Assembly. Illinois Code 35 Revenue 200/21-15
On a $5,000 unpaid installment, that works out to $37.50 for every month, or part of a month, you’re late. The amount is calculated on whatever balance remains, so partial payments help. The Treasurer’s office accepts them through the website, and each one lowers the figure that future interest is calculated against.6Cook County Treasurer’s Office. Cook County Treasurer’s Office Accepts Partial Property Tax Payments on Website If you can’t cover the full bill by the due date, pay what you can and keep paying down the rest.
One exception: active-duty members of the Illinois National Guard or U.S. military reserves deployed outside the continental United States are not treated as delinquent on installments that come due while they’re deployed. No interest accrues on those installments until 180 days after they return from active duty.5Illinois General Assembly. Illinois Code 35 Revenue 200/21-15
If a Mortgage Company Pays Your Taxes
If your lender collects property taxes through escrow, don’t assume the payment happens automatically. After each installment due date, log in to cookcountytreasurer.com and confirm the payment posted, and that it posted to the correct property.7Cook County Treasurer’s Office. Monitoring Your Mortgage Payments get sent to the wrong parcel, get missed entirely, or get duplicated. If your lender fails to pay, you still owe the tax.
Pulling Up Your Bill
Every parcel in the county has a 14-digit Property Index Number (PIN). It’s the key to looking up your balance, making payments, and verifying what posted.8Cook County Treasurer’s Office. Everything You Need to Know About Your Property Index Number or PIN Pay on the wrong PIN and your property stays flagged as delinquent while someone else’s account gets credited.
Your PIN is printed on prior tax bills and on the deed from when you bought the property.9Cook County Treasurer’s Office. About Your Property Index Number (PIN) Enter it on the Treasurer’s website to see your current balance, view your bill, and print a duplicate payment coupon.
If you’ve moved or changed names, update your record with the Treasurer by mail or in person at 118 North Clark Street, Room 112, Chicago, IL 60602.10Cook County Treasurer’s Office. Updating Your Name or Address An out-of-date address may mean no bill shows up in the mail. The tax is still due.
Ways to Pay
The payment channel you choose affects fees and, in one case, the date your payment is credited.
Online from a Bank Account
Paying through the Treasurer’s website by ACH debit from a checking or savings account is free.11Cook County Treasurer’s Office. Pay Online with Your Bank Account You get a digital confirmation as your receipt.
Online by Credit or Debit Card
The same site accepts credit and debit cards, but the processor charges a 2.1 percent convenience fee that is not refundable.12Cook County Treasurer’s Office. User Agreement for Credit/Debit Card Online Payment Service On a $5,000 bill that’s an extra $105.
At Chase Bank or a Community Bank
Nearly 400 Chase Bank branches in Illinois accept Cook County property tax payments, including locations outside the county. Bring a payment coupon, either the original from your bill or a duplicate printed from the Treasurer’s website. Screenshots of other payment pages are not accepted.13Cook County Treasurer’s Office. Making Cook County Property Tax Payments at Chase Bank A list of participating community banks appears on the Treasurer’s site.
By Mail
Send a check or money order with the payment coupon to the P.O. Box printed on your bill. One coupon and one check per PIN per envelope.14Cook County Treasurer’s Office. Pay by Mail or in Person
The postmark rule is important and strict. Only a United States Postal Service postmark counts for the due date. Payments sent by FedEx, UPS, or any other private carrier are credited on the day the Treasurer’s office receives them, not the day you shipped them.14Cook County Treasurer’s Office. Pay by Mail or in Person Postage meter marks don’t qualify either. If you’re mailing close to the deadline, go to a post office counter and ask for a hand postmark. Your canceled check is your receipt.
In Person
Pay in person at the Treasurer’s Office, 118 North Clark Street, Room 112, Chicago, IL 60602, open Monday through Friday, 9:00 a.m. to 5:00 p.m. Closed on weekends and county holidays.
If Taxes Stay Unpaid
Delinquent bills don’t sit on your account forever. Under Illinois law, the Cook County Treasurer runs an Annual Tax Sale where unpaid taxes from the immediately preceding tax year are sold to third-party buyers. The next Annual Tax Sale is anticipated for 2026.15Cook County Treasurer’s Office. Tax Sale General Information
At the sale, a buyer pays your delinquent amount plus interest and penalties and receives a tax lien certificate on your property. You don’t lose ownership right away. You have a redemption window, generally 30 months from the sale date for certificates issued on or after January 1, 2024, to pay back the full amount owed, including delinquent and current taxes, interest, penalties, and fees. The county can also charge a fee to produce the redemption estimate.
Miss the redemption deadline and the tax buyer can petition the court for a tax deed, which transfers ownership. Separately, properties carrying three or more years of unpaid taxes can be included in a Scavenger Sale, where accumulated debts are auctioned off starting at $250.15Cook County Treasurer’s Office. Tax Sale General Information Paying on time, or at least whittling down the balance quickly after a missed deadline, is what keeps a late installment from turning into a lost property.