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LexiState
formationUpdated 2026-03-31

Illinois LLC Minimum Members Requirement

What is the minimum number of members for an LLC in Illinois?

Illinois permits one member to form and operate an LLC. Under 805 ILCS 180/5-5, a single organizer who is at least 18 years old can establish an LLC. No minimum membership threshold exists; solo entrepreneurs can structure their business as a single-member LLC and receive full liability protection.


Single-Member LLC Formation

An organizer must be either an individual age 18 or older or another business entity. Foreign owners are permitted. When filing Articles of Organization with the Illinois Secretary of State, you'll identify at least one organizer—typically yourself in a single-member structure.

Single-member LLCs in Illinois receive identical liability protection and tax flexibility as multi-member LLCs. You maintain full control while your personal assets remain shielded from business liabilities.

Filing Requirements

File Articles of Organization with the Illinois Secretary of State, Department of Business Services. Required information includes:

  • LLC name with required designator (LLC, Limited Liability Company, or L.L.C.)
  • Principal place of business address
  • Registered agent name and Illinois registered office address
  • Organizer name, address, and signature
  • Effective date (optional)

Submit online at https://apps.ilsos.gov/llcarticles/index.jsp. The filing fee is $150.00 for standard processing (approximately 10 business days) or $250.00 total with expedited 24-hour service.

Before filing, verify your chosen name is distinguishable from existing entities using the Secretary of State's business search tool at https://apps.ilsos.gov/businessentitysearch/.

Next Steps After Formation

After approval, obtain an EIN from the IRS if you plan to hire employees or operate as a partnership for tax purposes. Register for state taxes with the Illinois Department of Revenue.

If operating under a name different from your LLC's legal name, file a DBA (assumed name) with the Secretary of State for $120.00.

Contact Information

Illinois Secretary of State
Limited Liability Division
Phone: (217) 524-8008
Address: 501 S. Second St., Rm. 350, Springfield, IL 62756


This is general information, not legal advice.