How to Look Up an LLC in Illinois (2026)
You can look up an LLC in Illinois through the Business Entity Search database run by the Secretary of State. It's free, and it covers every LLC, corporation and partnership on file in the state.
This guide walks through every reliable way to search Illinois business records, from the online database to a direct call to the Business Services office. It also covers how to check whether a name is already trademarked before you file.
Each method pulls up slightly different details, so picking the right one saves time. Start with the database, since it covers the most ground.
Quick Summary
- Start with the Secretary of State's free Business Entity Search database before you file, sign a contract or reserve a name.
- Call the Business Services office directly if the online search doesn't answer your question.
- Check the state and federal trademark databases too, so your chosen name is clear before you commit to it.
How to Search an LLC in Illinois
Illinois keeps its LLC records in one place: the Secretary of State's Business Entity Search database. The table below shows the five ways to search it.
| Search Method | What to Enter | Best For |
|---|---|---|
| Business name | Full or partial LLC name | General lookups and name checks |
| Registered agent | The agent's name | Finding every LLC tied to one agent |
| File number | The Secretary of State file number | An exact match when you already have it |
| Manager, president or secretary | That person's name | Finding LLCs tied to one person |
| Keyword | A word or phrase from the name | Broad searches when you don't know the exact name |
1. Search the Business Entity Database
Pick a search type first, then type in your search term and run the query. Trying more than one search type helps if your first attempt turns up nothing useful.
Open any result and you'll see the entity's status, its formation date, its registered agent and its registered office address. That record is public, and a Certificate of Good Standing for the same entity costs $25.
A search by registered agent is useful before you form an entity too. If you're comparing registered agent services in Illinois, this search shows which companies a given provider already represents.
If you're picking a new name before you start an Illinois LLC, state law sets three rules for it. Your name has to include "LLC," "L.L.C." or "Limited Liability Company." It can't contain "Corp.," "Inc.," "Ltd." or "Limited Partnership."
The name also has to read as distinct from any name already on file, reserved or registered as an assumed name [1]. Reserving a name locks it in while you finish your paperwork.
You can hold an available name for 90 days. File Form LLC-1.15 with a $25 fee, or pay $50 to get it processed the same day [2].
Call the Illinois Secretary of State
Sometimes the database doesn't answer your question, and calling is faster than digging through search results. Reach the general line at 800-252-8980, which serves both the Springfield and Chicago offices.
For a quick name-availability check specifically, call 217-524-8008 instead. Both offices keep business hours from 8 a.m. to 4:30 p.m., Monday through Friday.
3. Try a Broader Search
A few other tools round out your search when the database and a phone call still leave a gap:
- Company naming services: online tools that flag whether a name is likely available before you file.
- Search engines and social media: a fast way to see whether a business is actively operating and how.
- Domain name search: checks whether the name you want is already taken as a website address.
How to Check if a Business Name Is Trademarked in Illinois
A state entity search only rules out identical or near-identical names on file with the Secretary of State. It doesn't rule out a trademark, so run a separate check before you build a brand around a name.
Search two places. The USPTO's Trademark Search tool covers federally registered marks. Illinois also keeps its own Trademark Search database for marks registered at the state level.
1. Search the Illinois Trademark Database
Illinois registers trademarks and service marks separately from LLC names. A business name that clears the entity search can still infringe on one.
Search by registration number, or search by the mark's name as an exact match from the start. A partial-name search works too, since it can turn up a match anywhere in the name. You can also search by the registrant instead of the mark itself.
2. Search the Federal Trademark Database
Run the same name through the USPTO's tool too. A federal registration can also block your name even if no one in Illinois has claimed it.
Running both searches before you file, rather than after, is the cheaper habit to build. Fixing a naming conflict once you've printed signage and set up accounts costs a lot more than the few minutes either search takes.
Illinois isn't the only state with its own entity and trademark databases. Our guide to looking up an LLC walks through the equivalent tools for every other state.
FAQs
How Do I Reserve a Business Name in Illinois?
You reserve a business name in Illinois by filing Form LLC-1.15 with the Secretary of State. Reservation is optional. Skip it if you're ready to file your LLC right away and use it only when you need time to line up paperwork first.
How Do I Get a Certificate of Good Standing in Illinois?
You get a Certificate of Good Standing in Illinois by ordering one from the Business Services office for $25. It confirms your LLC is active and current on its filings.
Can I Look Up an LLC's EIN Number in Illinois?
No, you can't look up an LLC's EIN number through a public Illinois database. The IRS doesn't offer a general EIN search for private companies, so ask the business directly or check SEC filings if it's publicly traded.
References:
- https://www.ilga.gov/legislation/ilcs/fulltext.asp?DocName=080501800K1-10
- https://www.ilga.gov/legislation/ilcs/fulltext.asp?DocName=080501800K1-15
Thanks for including trademark checks in your steps. I almost registered a name without checking for trademarks. This saved me from a potential legal headache.