Illinois

Illinois LLC Naming Rules

Complete 2026 guide to Illinois LLC naming requirements — required designators, forbidden and restricted words, uniqueness rules, and how to check availability before filing.

Required Designators in Illinois

Your Illinois LLC name must end with one of these official designators:

LLC

L.L.C.

Limited Liability Company

Forbidden and Regulated Words

Cannot use without state regulatory approval:

Bank, Trust (typically require state banking regulator approval)
Insurance (typically requires Department of Insurance approval)

Restricted Words (Require Licensing Board Approval)

Licensed professions (attorney, medical, engineer, architect) typically require the respective licensing board approval

Uniqueness Requirement in Illinois

Must be distinguishable from existing entities on file with the state Secretary of State.

Illinois-Specific Naming Rules

Check the state's Business Search tool before filing
Consider reserving the name if available in your state
Don't choose a name similar to an existing federally-registered trademark

Check Illinois LLC name availability — free

Run a free check against Illinois's business database plus USPTO federal trademarks in one search.

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FAQ

What must my Illinois LLC name include?

Your Illinois LLC name must include one of the following designators: LLC, L.L.C., Limited Liability Company. Most common: simply appending 'LLC' at the end (e.g., 'Acme Ventures LLC').

How do I check if a Illinois LLC name is available?

Search the Illinois Secretary of State's business name database online (most states offer free search). Also run a USPTO trademark search for federal conflicts and a .com domain check. FormifyAI's free name-search tool checks both state availability and trademark conflicts.

What words can't I use in my Illinois LLC name?

Illinois restricts or forbids: Bank, Trust (typically require state banking regulator approval); Insurance (typically requires Department of Insurance approval). These typically require approval from specific state regulatory boards (e.g., insurance commissioner, banking regulator) before use.

Can I use a similar name to an existing Illinois business?

No. Must be distinguishable from existing entities on file with the state Secretary of State. "Distinguishable" typically means the names must differ in more than just punctuation, spacing, or articles ('The', 'An', 'A'). Even if the state accepts the filing, you could face trademark lawsuits from the existing business.

Can I reserve a Illinois LLC name before filing?

Check the state's Business Search tool before filing

What if my preferred Illinois LLC name is taken?

Options: (1) Modify the name slightly to make it distinguishable. (2) File under a different legal name and operate as a DBA (fictitious business name). (3) Purchase the existing LLC if it's dormant. (4) Wait for administrative dissolution if the existing LLC is non-compliant. FormifyAI's LLC name generator can suggest 20+ alternatives in seconds.

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FAQ

What must my Illinois LLC name include?

Your Illinois LLC name must include one of the following designators: LLC, L.L.C., Limited Liability Company. Most common: simply appending 'LLC' at the end (e.g., 'Acme Ventures LLC').