Illinois property taxes are due twice a year, with payments split between early summer and late fall

In Illinois, property owners pay taxes in two installments rather than one annual bill. The first installment is due around June 1, and the second is due around September 1. Both dates are firm important date—payments received after these dates are considered late and subject to penalties and interest charges.

The exact due dates can shift slightly depending on the day of the week and your county's specific payment schedule, so checking with your local county assessor or treasurer's office confirms the precise important date for your property. Most counties mail tax bills 30 to 45 days before the due date, giving you time to plan the payment.

Key Takeaways

  • Illinois property taxes are split into two payments: the first due around June 1 and the second around September 1 each year.
  • Payments made after the due date incur a penalty of 1.5 percent per month, plus interest at the rate set by the Illinois Department of Revenue.
  • Your county treasurer's office collects the payment, and you can pay by mail, in person, or online depending on what your county offers.
  • If you own a home with a mortgage, your lender may pay taxes from an escrow account, so confirm whether you or the bank handles the payment.
  • Property tax bills are mailed 30 to 45 days before each due date, so watch for the bill to arrive and verify the amount before paying.

How the two-installment system works

Illinois splits the property tax year into two periods to spread the burden across the calendar. The first installment covers taxes for January through June, and the second covers July through December. Each bill is calculated based on your property's assessed value and your local tax rate, which varies by county, school district, and municipality.

You receive a separate bill for each installment. The first bill typically arrives in April or May, and the second in July or August. Both bills show the amount due, the due date, and payment instructions specific to your county. If you do not receive a bill, contact your county treasurer's office—the bill's absence does not erase the debt.

Penalties and interest for late payment

Illinois law imposes a 1.5 percent penalty per month on any property tax payment received after the due date. This penalty is calculated from the due date forward, so a payment 10 days late incurs the full 1.5 percent charge. Interest accrues on top of the penalty at a rate set annually by the Illinois Department of Revenue, which has ranged from 5 to 9 percent in recent years depending on market conditions.

If taxes remain unpaid for a full year, the county may file a tax deed sale, which can result in loss of the property. Avoiding late payment is far simpler than dealing with the consequences. If you know you will miss a important date, contact your county treasurer when ready—some counties offer payment plans or short extensions in hardship situations, though these are not may provide.

Where and how to pay your property taxes

Payment methods vary by county. Most Illinois counties accept payment by mail to the county treasurer's office, in person at the treasurer's office during business hours, and increasingly online through the county's website or a third-party payment processor. Some counties also accept payment by phone or automatic bank draft if you set it up in advance.

When paying by mail, send your check or money order to the address listed on your tax bill at least one week before the due date to account for mail delivery time. Payments are considered received on the date the treasurer's office receives them, not the date you mail them. If you pay online, confirm that the payment has posted to your account before the important date—processing delays can occur, and you are responsible for ensuring timely receipt.

If your mortgage lender pays your taxes

Many homeowners with mortgages do not pay property taxes directly. Instead, the lender collects a portion of the tax bill each month as part of the mortgage payment and holds it in an escrow account. When the tax bill is due, the lender pays it on your behalf from that account.

If your lender handles tax payments, you will not receive a bill addressed to you—the bill goes to the lender. You are still responsible for verifying that the payment was made on time. Review your mortgage statement each month to confirm the escrow balance is adequate. If the lender underfunds the escrow, you may receive a bill for the shortfall, and you will owe it when ready. Contact your lender if you have questions about whether they are paying your taxes or if you need to pay them yourself.

What to do if you miss a important date

If you realize you missed the due date, pay as soon as possible. The penalty and interest will be added to your bill, but the sooner you pay, the less additional interest accrues. Contact your county treasurer's office to confirm the current amount owed, including penalties and interest.

Do not ignore a missed payment. If taxes remain unpaid for 18 months, the county may file a tax deed sale notice, which is a public notice that your property may be sold to recover the debt. At that point, you have limited options to stop the process. Paying when ready after missing a important date is far less costly than dealing with a tax deed sale.

Finding your county treasurer and payment details

Each of Illinois's 102 counties has its own treasurer's office, and payment procedures and important date can differ slightly. To find your county treasurer's contact information and payment options, search online for "[Your County Name] Illinois Treasurer" or visit your county's official website.

The Illinois Department of Revenue also maintains a list of county assessors and treasurers on its website. Call your county treasurer's office directly if you have questions about your bill, the due date, payment methods, or what to do if you cannot pay on time. They can also tell you whether your county offers online payment, automatic draft, or other conveniences.

Frequently Asked Questions

What happens if I pay one installment but not the other?

Both installments are separate bills with separate due dates. If you pay the first but miss the second, the second bill accrues penalties and interest starting from its due date. The county will pursue collection on the unpaid amount, and both bills must be current to avoid a tax deed sale.

Can I pay my property taxes online in Illinois?

Many Illinois counties offer online payment through their treasurer's website or a third-party processor, but not all. Check your county treasurer's website or call their office to confirm whether online payment is available and what fees, if any, explore. Payment by mail and in-person payment are always options.

What if I disagree with the amount on my property tax bill?

You can file a formal objection with your county assessor's office, but you must still pay the bill by the due date to avoid penalties. The objection process is separate from payment. Contact your county assessor to learn the important date for filing an objection and what documentation you need to support your claim.

Do I have to pay property taxes if I own the land outright with no mortgage?

Yes. Property taxes are owed by the property owner regardless of whether there is a mortgage. The lender does not own the property—you do—so you are responsible for the tax bill. If you do not pay, the county can file a tax deed sale even if the property is fully paid off.

What is the penalty if I pay late?

Illinois charges 1.5 percent per month as a penalty on late property tax payments, plus interest at a rate set by the Illinois Department of Revenue. Both are calculated from the original due date. A payment 30 days late will include a 1.5 percent penalty plus one month of interest on top of the original tax amount.