Kendall County Property Tax, DBA Filing and Business Incentives Guide

Kendall County lies directly south of Kane County and includes Yorkville, Oswego and part of Montgomery. Its offices are consolidated in Yorkville, and its rules differ from Kane and Will in ways that matter: no partial tax payments, a lower fee to register a trade name, and a local incentive program for small employers. This guide explains Kendall County property tax, how to challenge an assessment, how to register an assumed business name and what the county offers expanding businesses.

Who handles what in Kendall County?

The county government campus is in Yorkville, and county hours are Monday to Friday, 8:00 am to 4:30 pm.

What are Kendall County property tax dates and penalties?

Taxes are billed one year behind. For 2025 taxes payable in 2026, bills were mailed May 5, 2026 and could be paid from that date. The Treasurer's schedule sets out the penalty by payment date:

After September 30 the office accepts only cash, cashier's check, money order or certified check, and the schedule shows the tax sale on October 26. Online card payment closed October 15, 2026 and carries a convenience fee set by the processor, not the county. Include your parcel number on every check and send only the coupon.

For example, an owner with a $6,000 bill owes $3,000 per installment. Paying the first on August 15 falls in the 4.5% band, so the penalty is $135 and the total is $3,135. Our Illinois compliance calendar tracks these dates across counties.

How do exemptions and assessment appeals work in Kendall County?

Township assessors value property at the statutory 33.33% median level of fair cash value. You can check an assessment by dividing it by that level; if the result exceeds what your property would sell for, you may be over-assessed. Steps:

1. Review the township's published assessment and call the township assessor.
2. If the issue is not resolved, file the residential or commercial complaint form with the Board of Review.
3. File before the township's final date, which the county sets at 30 days from publication; after that the Board cannot accept complaints.
4. Attend any hearing, then compare the decision with your records.

Exemptions reduce the equalized assessed value. The county's page lists general homestead, home improvement (added value of up to $75,000 a year, available for four years and certified by the assessor with no separate application), senior, senior freeze, disability and veteran exemptions, and notes that your driver's license must show the property address to receive a homestead exemption. Dollar limits are set by statute, so check the county's current forms.

How do you register an assumed business name in Kendall County?

A sole proprietor or partnership using a name other than the owners' real names files an assumed name certificate with the County Clerk. Corporations and limited partnerships file with the Secretary of State instead.

1. Complete the application with the business name, physical address, type of product or service, and every owner's name and home address.
2. All owners sign before a notary.
3. File with the County Clerk with the $5.00 fee and take away the publication notice.
4. Publish once a week for three consecutive weeks in a Kendall County newspaper; the first notice must appear within 15 days.
5. Make sure the publisher's certificate reaches the clerk within 50 days; failure voids the registration.
6. Receive the Certificate of Ownership of Business.

Changes use a supplemental application with no extra fee, and publication is needed when the change affects 25% or more of ownership. The clerk also reminds owners to contact the city or village for local licensing. See our assumed name guide.

What permits and incentives does Kendall County offer?

• Food: the Health Department permits and inspects all food service facilities, food trucks and temporary event vendors in the county, and offers a county-wide mobile food permit (the vendor still needs permission from the municipality or landowner). Cottage food operators register under Illinois law.
• Building and zoning: the county department covers unincorporated areas only; inside Yorkville, Oswego or Montgomery, use the village building department.
• Loans: a below-market loan of up to $15,000 per job created or retained, up to 49% of project cost, with collateral required.
• Property tax abatement: qualifying distribution and logistics, manufacturing and headquarters projects may receive a three-year abatement of 75%, 50% and 25%, based on jobs, investment, use and expected tax revenue.
• State programs: the county points to the Illinois EDGE tax credit, REV Illinois and the AIM manufacturing credit.

The Kendall Economic Development Alliance lists the Illinois SBDC at Waubonsee Community College among its partners.

What sales tax rates apply?

Kendall County's own row in the state rate file is 7.25% for general merchandise and did not change on August 1, 2026, because the regional transit increase that day covered Cook, DuPage, Kane, Lake, McHenry and Will counties only. Rates by town in the Illinois Department of Revenue file: Oswego 8.50%, Yorkville and Montgomery 8.25%, and the Kendall part of Plainfield 8.75%. Read our Illinois sales and use tax guide.

Which towns are in Kendall County?

• Yorkville, the county seat
• Oswego, which also reaches into Will County
• Montgomery, shared with Kane
• Plainfield, Aurora and Joliet, which each have a Kendall section

Mistakes to avoid

• Sending half a payment and assuming the balance can follow.
• Missing the September 30 switch to certified funds.
• Registering a trade name without checking the 15-day publication window.
• Assuming a Kane or Will County rule applies in Kendall.

How we can help

Our firm, based in the Aurora and Fox Valley area, supports Kendall County owners with U.S. returns, entity setup, payroll and sales tax, and bookkeeping. If you also hold property or accounts in India or Canada, we coordinate with your Canadian CPA or Indian Chartered Accountant so the three filings agree. See business formation and registrations and payroll and employer compliance.

Frequently asked questions

General information only. It is not tax, legal, accounting or immigration advice for your situation, and rules change; confirm the current rules with the official source or a licensed professional in the relevant country.