To register a DBA in Illinois, sole proprietors and general partnerships file an assumed name certificate with the county clerk in every county where they do business, while corporations and LLCs file an application with the Illinois Secretary of State. The tracks are entirely separate, and county filings carry an extra step: a newspaper notice that must be published and proven, or the registration is void.
Figure Out Which Filing Applies to You
Your business structure decides where you file. Get this wrong and you’ll have paid for a registration that doesn’t cover you.
Sole proprietorships and general partnerships file at the county level. You need a certificate if you operate under any name other than your full legal name, or the full legal names of all partners. Jane Doe operating as “Jane’s Bakery” needs to file; Jane Doe operating as “Jane Doe” does not.1Cook County Clerk. Assumed Business Name Registration
Corporations and LLCs file at the state level with the Secretary of State. An assumed name here means any name other than the exact name on file with that office.2Illinois General Assembly. Illinois Code 805 ILCS 180 – Limited Liability Company Act – Section 1-20 Two things don’t count as assumed names: using a trademark or service mark you own or license, and using a division name that avoids words like “corporation,” “LLC,” or “limited” as long as you also disclose the entity’s real name.3Justia Law. Illinois Code 805 ILCS 5 – Business Corporation Act of 1983 – Section 4.15
Check That the Name Is Available
Before filing, confirm the name isn’t already taken in the system you’re filing in. The Secretary of State runs a free online Business Entity Search that covers corporate names, LLC names, and state-level assumed names.4Illinois Secretary of State. Business Entity Search For county filings, contact the county clerk’s office; most counties keep their own separate registries.
An available name at the county level doesn’t mean it’s available statewide, and the reverse is also true. The two systems don’t share data. Neither one checks federal trademarks.
Naming Rules
LLC assumed names cannot include “Corporation,” “Corp.,” “Incorporated,” “Inc.,” “Ltd.,” or “Limited Partnership,” and cannot include words suggesting banking activity such as “Trust,” “Trustee,” or “Fiduciary” without the appropriate license.5Illinois General Assembly. Illinois Code 805 ILCS 180 – Limited Liability Company Act – Section 1-10 Names cannot imply government affiliation, and terms tied to regulated professions like engineering or architecture require the corresponding license. Corporations face similar rules under the Business Corporation Act. The name also cannot be identical or deceptively similar to one already registered in the same system; the Secretary of State will reject applications that are too close to existing filings.
County-Level Registration: Sole Proprietorships and Partnerships
County filings are governed by the Assumed Business Name Act.6Justia Law. Illinois Code 805 ILCS 405 – Assumed Business Name Act The process has three parts: file the certificate, publish a newspaper notice, then file proof that you published it.
What the Certificate Contains
Your assumed name certificate lists the name you’ll do business under, the true full legal name of every owner, a post office address for each owner, and every business address in that county.7Justia Law. Illinois Code 805 ILCS 405 – Assumed Business Name Act – Section 1 It has to be signed in front of a notary. Many county clerk offices keep a notary on-site, so a single visit usually covers it.
How to File and What It Costs
You can file in person, by mail, and in some counties online. Cook County accepts online applications.1Cook County Clerk. Assumed Business Name Registration Fees vary by county; Cook County charges $50. Confirm the amount with your county clerk, and if you mail your filing, send a check or money order.
If your business operates in more than one county, file a separate certificate with each county clerk. A single county filing does not cover the state.
The Newspaper Publication Step
After filing the certificate, publish a notice in a newspaper of general circulation in the county. The notice runs once a week for three consecutive weeks, and the first publication must appear within 15 days of your filing date.7Justia Law. Illinois Code 805 ILCS 405 – Assumed Business Name Act – Section 1
Then you have to prove it. Within 50 days of your original filing date, file the proof of publication with the county clerk. The newspaper provides a notarized Certificate of Publication and an original clipping of the notice. In Cook County, photocopies are not accepted; you need the originals.1Cook County Clerk. Assumed Business Name Registration
Miss this step and your certificate is void.7Justia Law. Illinois Code 805 ILCS 405 – Assumed Business Name Act – Section 1 Not incomplete. Void. You’d have paid the filing fee, submitted every form, and still have no valid registration. Budget for the newspaper cost on top of the county fee; rates depend on the paper.
State-Level Registration: Corporations and LLCs
Corporations and LLCs skip the county clerk and file with the Secretary of State. Corporations are governed by the Business Corporation Act; LLCs by the Limited Liability Company Act.3Justia Law. Illinois Code 805 ILCS 5 – Business Corporation Act of 1983 – Section 4.15 There is no newspaper publication requirement at the state level.
What the Application Contains
The application to adopt an assumed name has four required pieces: your entity’s true legal name, the state or country where it was organized, a statement that the entity intends to do business under an assumed name, and the assumed name itself.2Illinois General Assembly. Illinois Code 805 ILCS 180 – Limited Liability Company Act – Section 1-20 For corporations, the board of directors has to pass a resolution authorizing the assumed name before the application goes in.3Justia Law. Illinois Code 805 ILCS 5 – Business Corporation Act of 1983 – Section 4.15
How to File and What It Costs
Domestic and foreign LLCs in good standing can file electronically through the Secretary of State’s website, or mail forms to the Springfield office. The LLC filing fee is $120.8Illinois Secretary of State. Adopting an Assumed LLC Name Corporation fees are set separately under the Business Corporation Act; check the current fee schedule with the Secretary of State. Processing runs from a few business days for electronic filings to several weeks by mail.
What Happens If You Don’t Register
Operating under an unregistered assumed name in Illinois is a Class C misdemeanor, and each day counts as a separate offense. The practical exposure is often worse than the criminal one: someone suing you can file directly against the business under its assumed name, name any known owners, and designate the rest as “unknown owners.” A judgment from that suit becomes a personal judgment against every named owner and is immediately enforceable against the business’s property, including a lien on any real estate held in the business’s name.9Justia Law. Illinois Code 805 ILCS 405 – Assumed Business Name Act – Section 6
Renewals and Changes After Filing
County Certificates
County-level assumed name certificates for sole proprietorships and partnerships have no expiration date. But if your name, address, or ownership changes, you file a new certificate and go through the publication process again for that change.7Justia Law. Illinois Code 805 ILCS 405 – Assumed Business Name Act – Section 1 Move to another county or open a location there, and you file in that county too.
State Registrations
State-level assumed names for corporations and LLCs expire on a rolling schedule tied to the entity’s anniversary month in the next calendar year divisible by five. An LLC with a March anniversary that adopts an assumed name in 2024 can use it until March 1, 2025. If the filing happens within the two months before that anniversary month in a year divisible by five, the name extends to the following cycle instead.2Illinois General Assembly. Illinois Code 805 ILCS 180 – Limited Liability Company Act – Section 1-20
Renew within the 60 days before the assumed name expires; the renewal is usually handled with your annual report.3Justia Law. Illinois Code 805 ILCS 5 – Business Corporation Act of 1983 – Section 4.15 For LLCs, if you miss the renewal and haven’t paid after receiving a notice from the Secretary of State, the office adds a $100 late fee per name. If the fee and penalty are still unpaid 60 days after that notice, you lose the right to use the assumed name.2Illinois General Assembly. Illinois Code 805 ILCS 180 – Limited Liability Company Act – Section 1-20
A DBA Is Not a Trademark
Registering an assumed name in Illinois gives you the right to do business under that name in the state. It does not give you ownership of the name as a brand. A federal trademark registered with the U.S. Patent and Trademark Office protects the name nationwide within your industry and stops others from using a confusingly similar mark.10United States Patent and Trademark Office. Trademark or Trade Name? If the business name is central to how customers identify you, a DBA filing is a starting point, not the whole answer.