Illinois Secretary of State
Illinois Business Entity Search
Last updated . Register data is refreshed nightly.
Check whether a business name is already on file with the Illinois Secretary of State. Free, no account, all entity types.
Illinois Business Entity Search
Search the state's official business records.
Illinois runs its register at apps.ilsos.gov, free and without an account. It offers more ways in than any other state, and four of them are people.
Eight ways to search, and half are names of humans
Pick one before you type anything. The form will not submit without a method, and nothing is preselected:
Business Name · Registered Agent · President · Secretary · Manager · File Number · Keyword · Partial Word
Most registers let you search a company. Illinois lets you search a person and find what they are attached to. Only Oregon and Arizona offer anything comparable, and neither offers four separate roles.
That is the tool if you are checking who you are about to do business with, working out what else a director is involved in, or seeing how many companies a registered agent carries.
Note also that Keyword and Partial Word are listed as methods in their own right rather than as match settings, which is an unusual way to build a search and means you choose your breadth up front.
It returns 500 and tells you
Search something broad and a banner appears:
The first 500 records have been returned. Please refine your search to limit the results
That is the honest version of what several states do silently. Hawaii cuts at 300 without a word; Texas refuses to list anything at all past a count. Illinois gives you a large sample and says plainly that it is a sample.
After the search you get a Filter by Entity dropdown, a page size up to 100, and a Search box that narrows what is already on screen.
Every column sorts, and the agent is one of them
Results carry the file number, entity type, entity name, entity status, registered effective date and registered agent, and every column sorts.
Because the agent is in the grid, you can order a page of results by agent and see at a glance which companies share one. That is a reverse lookup you get for free, without opening anything.
LLC (MST) and LLC (OLD)
The entity type column shows both against different companies, and both are limited liability companies.
We have not found the state explaining the distinction anywhere, so we are not printing a meaning for it. If you see one against a company you care about, ask the Department of Business Services rather than trusting a guess, including ours.
The record opens on its emptiest tab
Open an entity and you get the name, principal address, file number, status with the date it took effect (REVOKED on 12-11-2009 rather than a bare REVOKED), entity type, whether the LLC is domestic or foreign, organization or admission date, jurisdiction, duration, annual report filing date and year, the agent with a full address, and an Agent Change Date recording when the agent last changed.
Then a row of tabs: Available Services, Managers, Old LLC Name, Assumed Name, Series Name, File History.
It opens on Available Services, which is often empty and reads like the end of the page. The five beside it hold everything:
- Managers names the people running the company
- Old LLC Name carries former names
- Assumed Name carries the DBAs, which Wisconsin does not hold at all
- Series Name gives each series of a series LLC its own place, as Iowa does
Individual searches only
The overview states the database is available for individual searches only and may not be used to copy or download bulk information. Single lookups are what it is for.
It covers corporations, not-for-profits, limited partnerships, LLCs and LLPs. Sole proprietors are not in it.
Who decides
Eight search methods is thorough evidence and still not a ruling. Acceptance is decided by the Department of Business Services on examining the filing, under the Illinois Limited Liability Company Act, 805 ILCS 180.
Before you rely on it
Choose a method deliberately. Nothing is preselected and the eight are not equivalent.
Use the people searches if your question is about a person rather than a name.
Sort by registered agent to see shared agents without opening records.
Click past Available Services. The first tab is usually the empty one.
Illinois filing facts
| Filing | Standard | 24-hour service |
|---|---|---|
| Articles of Organization | $150.00 | $250.00 |
| Articles of Organization, series LLC | $400.00 | $500.00 |
Illinois prices speed as a separate product rather than a surcharge: $150 with ten business day processing, $250 for 24 hours. A card payment adds a processor fee the state does not state the amount of.
The series LLC premium is steep: $400 against $150, where Wyoming charges $10 per series on top of an ordinary $100 formation. If you are building a structure that needs several series, that gap is worth doing arithmetic on before choosing a state.
We are not quoting an annual report fee. The state's LLC annual report instructions page has a Fees heading carrying only payment-method text and no amount, so we have nothing verified to print.
199,030 applications came in over the 52 weeks to 26 September 2026: 796 a business day, up 12.2%, putting Illinois 6th of 51 by volume.
What the register will not tell you
Illinois has 136,960 live registered marks, and one city carries them:
| word | live marks | times more common than nationally |
|---|---|---|
| illinois | 720 | 25x |
| chicago | 2,783 | 23x |
| association | 1,423 | 3x |
| guard | 655 | 3x |
| master | 749 | 2x |
| blue | 1,446 | 2x |
| plus | 1,188 | 2x |
Chicago appears in 2,783 marks, nearly four times as many as the state's own name, and it accounts for 34.9% of all Illinois filings. After those two the list drops straight to the ordinary: blue, plus, master and guard all sit at two or three times normal.
Association at 1,423 marks is the one worth a second look. Illinois is home to a great many trade bodies and professional associations, and the word is correspondingly crowded. If your name uses it, check the federal register.
What the Illinois portal looks like
Captured from the live register. Personal names and addresses are blacked out; everything else is as the state publishes it.
Illinois Secretary of State business services
Business registrations in Illinois are held by the Illinois Secretary of State, which maintains the public register this page searches, accepts new filings, and issues the certificates a bank or a counterparty may ask you for. Contact them directly for anything that has to be official.
| Business entity search | apps.ilsos.gov/businessentitysearch |
|---|---|
| Phone | (800) 252-8980 |
| Address | Services Springfield Springfield Office 501 S. Second Street Room 350 Springfield, IL 62726 |
| Office hours | 8:00 a.m.-4:30 p.m. |
| LLC filing fee | $150 |
| Processing | 5-10 business days |
The office handles registration, not disputes. If a name is already taken, they will tell you it is unavailable but not who holds it beyond what the public record shows, and they will not advise on whether your name infringes someone’s mark.
Common questions about Illinois business entity searches
How do I check if an LLC exists in Illinois?
Search the name on this page or on the state's own portal. What Illinois does by default is worth knowing before you read the result: none preselected; the form refuses to submit without a method. A match means the entity is on file, and its status line tells you whether it is still active.
How do I verify a company is registered in Illinois?
Search the name, then open the record rather than reading the results line. Entity name, principal address, file number, status with the date it took effect (REVOKED on 12-11-2009 rather than a bare REVOKED), entity type, type of LLC as domestic or foreign, organisation or admission date,…. The status on the record is the one to trust: a dissolved company still appears in a search and still holds its name.
Does a clear search mean my Illinois business name is approved?
Not on its own. A no-match result means the name is not on the Illinois register today, which is a preliminary answer rather than approval: Illinois Secretary of State decides when it reviews the filing. Worth knowing about Illinois in particular: it returns the first 500 records and says so in a banner: The first 500 records have been returned. Please refine your search to limit the results. That is the honest version of what Hawaii does silently at 300. Refine rather than assume you have seen everything.
Can I look up who owns a business in Illinois?
Illinois carries a Managers tab on the record, alongside tabs for old names, assumed names and series.
How much does it cost to register a business name in Illinois?
Illinois Secretary of State charges $150 to file the Articles of Organization, which is the document that forms the company, and currently takes 5-10 business days to process. Reserving a name beforehand is a separate and smaller fee. Confirm the figure with the state before you file: schedules move.
Sources
- Illinois business entity search, the official register this page queries.
- Filing fees and processing times: Illinois Secretary of State, Information for Forming an LLC Online, verified 2026-09-10. Current schedules are published by the Illinois Secretary of State.
- Formation activity: Census Bureau Business Formation Statistics, retrieved via FRED at the Federal Reserve Bank of St Louis.
- Federal trademark data: United States Patent and Trademark Office, 3,374,058 live registrations cross-referenced against the state registers. Live excludes both abandoned applications and cancelled registrations.
- Office contact details: compiled from published directories and not yet confirmed against the contact page published by the Illinois Secretary of State. Telephone the office before relying on an address.
- Naming statute: 805 ILCS 180/1-10, published by the state.
- State seal: public domain image via Wikimedia Commons.