Illinois Business Name Search
Data verified July 25, 2026 · Official database: Illinois Secretary of State
LLC filing fee
Name reservation fee
Reservation hold
Quick answer: Illinois runs name checks through the Secretary of State’s Business Entity Search, and the statute behind it is unusually specific about wording. Beyond requiring an LLC ending, 805 ILCS 180/1-10 forbids “Corp.,” “Inc.,” “Ltd.,” “Co.” and “L.P.” anywhere inside the name, and it measures your name against assumed names filed with the state as well as entity names. The Secretary of State makes the call when it reviews your Articles of Organization.
How to check a name in Illinois
The checker above is your quick first pass. The four screens below follow the Secretary of State’s own Business Entity Search. Illinois opens with a choice most state portals do not offer, eight search methods in a single radio group, so the first thing you decide is which index you want to read. What you find here is preliminary; the Secretary of State decides the name at filing.
Step 1: Pick a search method
Open Business Entity Search. The page opens on “Search for a Business Entity” with a required “Choose a Search Method” group: Business Name, Registered Agent, President, Secretary, Manager, File Number, Keyword, and Partial Word. Only one method runs at a time, and Business Name is the one selected by default for a name check. Keyword and Partial Word are the wider nets to come back to.
Step 2: Enter the words, not the ending
Type the distinctive words into the “Start a New Search” field and leave the ending off. That matters more in Illinois than elsewhere: the statute bars other entity words outright, so an ending was never going to separate your name from a close match. Choose Submit. If the first pass looks clean, run the same words again under Partial Word to catch a conflict sitting in the middle of a longer name.
Step 3: Read the Entity Status column
Results arrive as a sortable table with a “Show 100 entries” control and columns for File Number, Entity Type, Entity Name, Entity Status, Registered Effective Date, and Registered Agent. Two columns carry the weight. Entity Type mixes LLC, CORP and NFP rows together, which is correct rather than noise, because the Illinois comparison reaches corporate names too. Entity Status is unusually detailed, running through ACTIVE, WITHDRAWN, DISSOLVED, INVOLUNTARY DISSOLUTION and MERGED/CONSOLIDATED, so you can read what kind of record a near match is.
Step 4: Open the record and check its name tabs
Selecting a name opens Entity Information: File Number, Status, Entity Type, Type of Corp, Qualification Date, home State, Duration Date, Annual Report Filing Date and Agent Information. The record shown is a Washington corporation registered in Illinois as a FOREIGN BCA. Below it sit tabs for Available Services, Officers, Assumed Name, Old Corp Name and File History, and the middle two are the reason to open a record at all. A company can hold extra names there, they count in the comparison, and the results list never shows them.
Illinois LLC naming rules
The rules sit in 805 ILCS 180/1-10:
- Required ending: “limited liability company,” “L.L.C.” or “LLC.” A low-profit company organized under Section 1-26 uses “L3C” instead.
- Other entity words are barred: “Corporation,” “Corp.,” “Incorporated,” “Inc.,” “Ltd.,” “Co.,” “Limited Partnership” and “L.P.” may not appear anywhere in the name. Many states only require the right ending; Illinois also polices the rest of the wording.
- Characters: the name must use English-alphabet letters, Arabic or Roman numerals, or symbols the Secretary of State is able to reproduce.
- Distinguishable from five things on the Secretary of State’s records: LLCs with articles of organization on file, foreign LLCs admitted to transact business here, names held under an exclusive reservation, assumed names registered under Section 1-20, and corporate or assumed corporate names.
- What does no work: “limited,” “liability” and “company” cannot make a name distinguishable, and neither can a difference in articles, conjunctions, contractions, abbreviations, tense or number.
- Restricted words: “trust,” “trustee” and “fiduciary” are available only after meeting Section 1-9 of the Corporate Fiduciary Act.
- Who decides: Section 1-10(f) gives the decision to the Secretary of State. The exception is a certified copy of a final court decree establishing a prior right to the name, which sets the test aside.
Reserving a name in Illinois
A reservation is $25 on Form LLC-1.15 and holds the name for 90 days as an exclusive right. Two details are worth knowing before you pay. The hold is transferable by written notice, so it can move to another person or company while it runs, and the $25 cannot be credited toward any later filing fee. If the 90 days lapse and the name is still open, nothing stops you filing a fresh application to reserve it again.
Weigh that against the $150 Articles of Organization fee. At a sixth of the cost of forming, the reservation is a cheap hedge while a lease or financing settles, and unnecessary once you are ready to file.
Assumed names in Illinois
Illinois splits its DBA system down the middle, and which half you land in depends on your entity. An LLC or corporation adopts an assumed name centrally with the Secretary of State on Form LLC-1.20. A sole proprietor or general partnership instead files an assumed-business-name certificate with the county clerk in each county where it operates, under 805 ILCS 405, and publishes notice in a local newspaper.
One narrow exception is easy to miss. Section 1-10(a)(5) lets an LLC use a divisional designation or trade name without an assumed-name filing, provided the company also clearly discloses its own name.
The state fee is prorated in a way you will not see elsewhere. It runs $150, $120, $90, $60 or $30 depending on the anniversary year, because Illinois sets every registration to expire in the next calendar year evenly divisible by five. After that it renews at $150 every five years, roughly $30 a year.
A registration is disclosure, not ownership, and grants no exclusive trademark right. Its practical effect runs the other way: a state assumed name sits in the Section 1-10 comparison, so while yours is active the Secretary of State will not register a later name that is not distinguishable from it. County certificates carry no such statewide weight and are not centrally indexed, which is the gap to remember when a search comes back clean.
If your Illinois name is taken
- Do not reach for a different ending. “Inc.” and “Corp.” are barred outright in an LLC name here, so the usual workaround is unavailable. Change a word that carries meaning.
- Punctuation and grammar will not save it. Tense, number, abbreviations and articles are all disregarded, and so are “limited,” “liability” and “company.”
- Open the close records before conceding. The Assumed Name and Old Corp Name tabs show whether the block is the entity name itself or a secondary name attached to it.
- A court decree is the only override. Written consent from the other company does not clear the test in Illinois; a certified copy of a final court decree does.
If the words read clear, you can start your Illinois LLC with that name while the record still shows it open. Standard online formation runs about 10 business days, with a 24-hour service at $250 if the timing is tight.
Official Illinois sources
- Business Entity Search: the Secretary of State’s entity and assumed-name database
- 805 ILCS 180/1-10: the LLC name and distinguishability rule
- 805 ILCS 180/1-15: the 90-day reservation
- 805 ILCS 180/1-20: registration of an assumed name
- LLC publications and forms: Form LLC-1.15 and the $25 reservation fee
- Adopting an assumed LLC name: the prorated five-year fee schedule
An open Illinois name is only yours once you file
Forming an LLC under your name is the only way to lock it in. Northwest handles the Illinois filing, registered-agent service, and paperwork.
Frequently asked questions
How do I check business name availability in Illinois?
Open the Secretary of State's Business Entity Search, choose "Business Name" from the eight search methods, and enter the distinctive words without an ending. Read the Entity Status column on every close row, then open the record and check its Assumed Name and Old Corp Name tabs, because names held there are part of the comparison and do not appear in the results list. The Secretary of State decides the name when it reviews your Articles of Organization.
Can an Illinois LLC name include "Inc." or "Corp."?
No. Illinois goes further than a required ending: 805 ILCS 180/1-10(a)(4) forbids "Corporation," "Corp.," "Incorporated," "Inc.," "Ltd.," "Co.," "Limited Partnership," and "L.P." anywhere in an LLC name. Swapping the ending to make a name look different is not an option here, so the distinctive words have to carry the difference.
How much does it cost to reserve a business name in Illinois?
Form LLC-1.15 costs $25 and holds the name for 90 days as an exclusive right that can be transferred by written notice. The $25 cannot be applied toward any other filing fee, and if the hold runs out with the name still open you may file a fresh application to reserve it again. Forming the LLC is a separate $150 for the Articles of Organization.
Do assumed names appear in the Illinois business search?
State assumed names do. An LLC or corporation that adopts an assumed name files it with the Secretary of State, where it joins the same entity records used for the distinguishability screen. County assumed-business-name certificates filed by sole proprietors and general partnerships sit in each county clerk's records instead, so they are not in the state search at all.
Who decides whether two Illinois business names are too similar?
The Secretary of State does, and the statute says so directly at 805 ILCS 180/1-10(f). A search result is information about the records, not a ruling, which is why a clear screen is preliminary. The one route around a conflict is a certified copy of a final court decree establishing your prior right to the name.