How to Do an Illinois LLC Name Search (2026 Guide)

Last Updated April 30, 2026 by the LLCForge Editorial Team. Verified against current state filing data and official Secretary of State sources.

Before you file Articles of Organization with the Illinois Secretary of State, your LLC name has to clear the state database at ilsos.gov/corporatellc. Standard online filings process in about 10 business days, expedited filings in 1 business day. Your name isn’t locked in until the state approves your formation. Pick a name that’s already taken or missing the LLC designator, and Illinois rejects the filing, holds your $150 fee in limbo, and you start over.

How to Search Illinois LLC Names: Step-by-Step

Step 1: Open the Illinois Business Entity Search

Go to ilsos.gov/corporatellc. On the left sidebar, click “Search” under the Business Services menu, then choose “Corporation/LLC Search/Certificate of Good Standing.” This is the same database the Secretary of State staff uses when reviewing filings, so what you see is what they see.

You don’t need an account to search. The lookup is free and unlimited.

Step 2: Enter the Core Name, Not the Full Name

Type the distinctive part of your name without “LLC” or “Limited Liability Company.” If you want “Prairie Path Consulting LLC,” search “Prairie Path Consulting” or even just “Prairie Path.” The system matches partial strings, so a shorter query catches more potential conflicts.

Don’t worry about capitalization. The Illinois search is not case-sensitive.

Step 3: Review the Results List

Illinois returns a list of entities with names that contain your search string. Each result shows the entity name, file number, type (LLC, Corporation, LP), and status (Active, Dissolved, Involuntarily Dissolved, Withdrawn). Click any name to see formation date, registered agent, and the entity’s principal address.

Pay attention to status. A dissolved entity’s name may still block you if dissolution was recent. Names of involuntarily dissolved entities can be reclaimed after a waiting period, but the safer move is to assume any active or recently dissolved match is a problem.

Step 4: Test Variations and Phonetic Matches

Illinois rejects names that differ only by punctuation, spacing, articles (“the,” “a”), or LLC designators. “Prairie Path LLC” and “ThePrairie Path L.L.C.” are not distinguishable. Run searches dropping “the,” swapping “&” for “and,” and testing plurals. If “Prairie Paths LLC” exists, “Prairie Path LLC” might still be rejected as too similar.

Step 5: Check the USPTO and Domain Availability

State availability isn’t the whole picture. Search the federal trademark database at tmsearch.uspto.gov for your proposed name. A trademark holder can force you to rebrand even if Illinois approves the LLC.

Check the .com domain at the same time. If a national company already owns the trademark and the domain, pick another name now rather than after you’ve ordered business cards.

Step 6: Reserve the Name (Optional)

If you’re not ready to file Articles of Organization but want to lock the name, file Form LLC-1.15 (Application to Reserve a Name) with $25. The reservation holds the name for 90 days. It’s not renewable, so don’t reserve until you’re within three months of filing.

Illinois LLC Naming Rules

Designator Requirement

Every Illinois LLC name must end with one of these: “Limited Liability Company,” “L.L.C.,” or “LLC.” Series LLCs use “Series Limited Liability Company,” “S.L.L.C.,” or “SLLC.” The designator is part of your legal name on every contract, invoice, and bank document.

You cannot use “Corporation,” “Corp.,” “Incorporated,” “Inc.,” “Limited Partnership,” or “L.P.” in an LLC name. Those signal different entity types.

Distinguishability Standard

Your name must be distinguishable on the records from every active LLC, corporation, LP, LLP, and reserved or registered name in Illinois. Distinguishable means more than a tiny tweak. The Secretary of State considers these differences insufficient:

• Adding or removing “the,” “a,” or “and”
• Changing punctuation, spacing, or capitalization
• Switching between singular and plural
• Switching between “&” and “and”
• Changing the LLC designator (LLC vs. L.L.C.)

Prohibited Words

Illinois bars words that imply a purpose your LLC isn’t authorized for. You cannot use “bank,” “banker,” “banking,” “trust,” “trustee,” “insurance,” “assurance,” “savings,” “Olympic,” or “Olympiad” without proof of regulatory approval from the relevant agency.

Words suggesting a government connection (“FBI,” “Treasury,” “State Department”) are also off-limits.

Restricted Words Requiring Approval

Some terms require sign-off from a licensing board before the Secretary of State accepts your filing. These include “medical,” “dental,” “engineering,” “architecture,” “law,” “attorney,” and other regulated profession terms. If you’re forming a Professional LLC (PLLC), you’ll file Articles of Organization for a Professional Limited Liability Company and submit a certified statement from the licensing authority.

What If Your Illinois LLC Name Is Already Taken?

Add a Geographic or Descriptive Modifier

“Lakeside Marketing LLC” taken? Try “Lakeside Marketing Chicago LLC,” “Lakeside Digital Marketing LLC,” or “Lakeside Marketing Group LLC.” Adding a real, distinguishing word usually clears the database. Don’t just add “Inc.” or swap “LLC” for “L.L.C.” That won’t satisfy the distinguishability rule.

Reserve the Name Before Someone Else Files

If you’ve cleared a name but aren’t ready to file Articles of Organization, submit Form LLC-1.15 with $25. The reservation runs 90 days and isn’t renewable. Expedited processing is available for an extra $100 if you need confirmation within 24 hours.

Standard reservations are processed by mail or in person at the Springfield or Chicago offices.

File a DBA (Assumed Name)

Your LLC’s legal name and the name on your storefront don’t have to match. Once your LLC is formed, you can file an Application to Adopt an Assumed Name (Form LLC-1.20) for $150 plus a per-year fee that depends on when in the five-year cycle you file. The assumed name lets a “Lakeside Marketing Group LLC” do business as “Lakeside Marketing” publicly.

Assumed names are renewed every five years.

Trademark Considerations

Illinois approval doesn’t grant trademark rights. If another business holds a federal trademark on a name similar to yours, even in a different state, they can demand you stop using it. Run a USPTO search before you commit. For names you plan to build a brand around, consider filing your own federal trademark application after formation.

After You Confirm Your Illinois LLC Name

Once your name clears, you’re ready to file Articles of Organization (Form LLC-5.5) with the Illinois Secretary of State for $150. You’ll also need an Illinois registered agent with a physical address in the state. See our Illinois LLC state guide for filing details, and our Illinois registered agent guide for agent options.

After formation, get a federal EIN from the IRS, draft an operating agreement (use our Illinois operating agreement guide), and open a business bank account. The full step-by-step is in how to start an LLC in Illinois.

Frequently Asked Questions

How do I know if my Illinois LLC name is actually available?

Run the name through the Secretary of State search at ilsos.gov/corporatellc, test variations (drop articles, change punctuation, swap singular/plural), and confirm no exact or near-exact match exists in Active or recently Dissolved status. Final approval only happens when the state accepts your Articles of Organization. The pre-filing search is a strong indicator, not a guarantee.

How long does an Illinois name reservation last?

90 days. Illinois doesn’t allow renewal. If your reservation expires before you file, you’d need to submit a new application and pay $25 again, assuming the name is still available.

Can my LLC name and DBA be different in Illinois?

Yes. Your LLC’s legal name (the one on your Articles of Organization) and your DBA (assumed name) can be completely different. File Form LLC-1.20 after formation. The fee is $150 plus a per-year amount based on the five-year renewal cycle.

Does my LLC name have to match my domain name?

No. The state doesn’t care about your domain. But practically, matching your LLC name to a .com you control makes branding and email simpler. Check domain availability before you file so you’re not stuck with “lakesidemarketingofchicago.net.”

What does “distinguishable on the record” actually mean in Illinois?

It means the Secretary of State staff, looking at your proposed name next to existing names, can tell them apart by more than punctuation, articles (“the,” “a”), spacing, plurals, or the LLC designator itself. “Smith Consulting LLC” and “Smith Consulting Inc.” are not distinguishable. “Smith Consulting LLC” and “Smith Strategy Consulting LLC” usually are.

Can I use the name of a dissolved Illinois LLC?

Sometimes. Voluntarily dissolved entities release their name back to the pool, but if dissolution was recent the name may still appear too similar to staff reviewing your filing. Involuntarily dissolved entities can technically reclaim their name within five years of dissolution, which is a reason to avoid those names. When in doubt, pick a different name or call the Department of Business Services at 217-524-8008 before filing.

This content is for informational purposes only and does not constitute legal or tax advice. Always consult a qualified professional for guidance specific to your situation.