Illinois Assumed Business Name (DBA) Filing: County Clerk Steps in Kane, DuPage, Will and Kendall

An Illinois assumed name is any business name that is not the real name of the owner or owners. If you are a sole proprietor or run a general partnership under a trade name, the Assumed Business Name Act requires you to file a certificate with the county clerk where the business operates and to publish a notice in a local newspaper. If you operate through an LLC or corporation, the county filing does not apply and the Secretary of State handles any assumed name instead. Getting this wrong is a Class C misdemeanor, and a missed publication deadline voids the registration.

Who must file an Illinois assumed name?

You must file when you transact business under any name other than the real full name of each individual owner. "Priya Sharma" operating as "Priya Sharma" needs nothing. "Fox Valley Bookkeeping" owned by Priya Sharma needs a certificate. A general partnership may use a name that includes the true names of the partners without a filing, but a trade name like "Riverbend Partners" does require one. The Act does not apply to corporations, LLCs, limited partnerships or limited liability partnerships organized in Illinois, or organized elsewhere and lawfully doing business here, which instead use the Secretary of State's assumed name process. Will County's clerk page lists professional service corporations among the business types that register with the county, so ask the clerk if you operate one.

How do you file an assumed name with an Illinois county clerk?

1. Pick the county. File in the county where the business is located; if you later open in another county, file there too and publish again.
2. Complete the certificate with the business name, a physical street address, the type of product or service, and each owner's true name and home address.
3. Sign before a notary. Every owner or partner signs. DuPage requires valid photo identification showing your current address.
4. File with the clerk and pay. Bring or mail the certificate. Kane, DuPage and Will accept mail filings; DuPage also accepts cards for a transaction fee.
5. Publish the notice once a week for three consecutive weeks in a general circulation newspaper in that county. The first notice must run within 15 days of filing.
6. Return the publisher's certificate to the clerk within 50 days from the filing date. Some newspapers send it directly, others give it to you; the burden is yours.
7. Receive the Certificate of Ownership once the proof is in. Banks usually ask for it before opening a business account in the trade name.

What do the four counties charge and require?

County pages: Kane, DuPage, Will and Kendall. State law (805 ILCS 405/3) sets a $5 fee for indexing and filing, which is why Kendall's fee matches; Kane, DuPage and Will currently publish $10. Newspaper charges for the three-week notice are extra and vary by paper. Under the statute, a change of an owner's name or address, or a new owner, needs an additional certificate, and a withdrawal or cancellation uses a supplementary certificate under oath.

What if you cannot publish your home address?

The Act allows a person who conducts business from a personal residence to list the county clerk as the default agent for service of process, instead of publishing the home address, if safety is at risk. The request must be on the clerk's form with reasons, accompanied by a court order or police report, and the clerk keeps the residence address confidential. The clerk may charge a nominal fee.

How do LLCs and corporations register an assumed name?

They file with the Secretary of State, online for LLCs in good standing. The LLC fee depends on the year of filing and runs until the first day of the company's anniversary month in the next calendar year evenly divisible by five:

For both LLCs and corporations, a change costs $25, a cancellation $5 and expedited handling adds $50; an LLC renewal is $150. Corporations adopt a name on form BCA 4.15 with the same fee schedule. The point of an assumed name for an LLC is often marketing or a second brand; the registered legal name still appears on contracts and tax filings. See Illinois LLC vs corporation if you are weighing an entity change.

Which dates should you track?

Worked example

Arjun, a Hyderabad native now living in Aurora, starts a tutoring business called "Fox Valley Math Club" as a sole proprietor in Kane County. He files on Monday, November 2, 2026 and pays $10; the first notice must run by Tuesday, November 17, and he must return the publisher's certificate by Tuesday, December 22. He runs the notice for three weeks in a Kane County weekly, receives the certificate on December 4 and delivers it to the clerk on December 9. His costs are $10 plus $1 notary plus the newspaper fee. If he later moved his lessons to a DuPage County storefront, he would file and publish again in DuPage.

Mistakes to avoid

• Filing in the wrong county, or assuming one filing covers all counties.
• Using a newspaper outside the county or not in the legal notice section.
• Forgetting to return the publisher's certificate.
• Trying to rename the business through a change filing; DuPage and Will require a new registration.
• Opening a bank account in the trade name before you hold the Certificate of Ownership.
• Forming an LLC later but keeping the old county assumed name active, and then skipping the annual report for the new entity.
• Using a trade name for payroll before registering the legal owner with the state employer agencies.

How we can help

We are based in the Aurora area and help sole proprietors and new LLC owners decide whether a county or Secretary of State filing applies, prepare the certificate, and set up bookkeeping and tax accounts in the right legal name. Where the business also has operations in Canada or India, we coordinate with your Canadian CPA or Indian Chartered Accountant. See business formation and registrations, bookkeeping and accounting and the startup checklist.

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.