How to Form an LLC in Illinois (2026)
Every Illinois LLC begins with a single filing: Articles of Organization, Form LLC-5.5, submitted to the Illinois Secretary of State's Department of Business Services, Limited Liability Division. The articles are governed by 805 ILCS 180/5-5 and the filing fee is $150. You can file online or send the paper form in duplicate. If you are structuring a Series LLC, the document changes to Form LLC-5.5(S) and the fee rises to $400.
Illinois runs on form numbers, so it pays to learn the short list early:
- Form LLC-5.5: Articles of Organization, $150. The formation filing itself.
- Form LLC-5.5(S): Articles of Organization for a Series LLC, $400.
- Form LLC-50.1: the annual report, $75, filed every year the company exists.
- Form LLC-1.36/1.37: Statement of Change of Registered Agent and/or Registered Office, $25, for whenever your agent details change down the road.
Step by Step: Organizing an Illinois LLC
- Confirm your name is available. The name needs "Limited Liability Company," "LLC," or "L.L.C." and must be distinguishable from every name already registered with the Secretary of State. Check the state database at ilsos.gov before committing to anything.
- Select a registered agent. Under 805 ILCS 180/1-35, the agent must be either an individual resident of Illinois or a business entity authorized to transact business here and registered with the Secretary of State. The LLC may not act as its own registered agent, the registered office address must be identical to the agent's business office address, and a PO box alone will not satisfy the requirement. Our registered agent page walks through the details.
- File Form LLC-5.5. Complete the articles with your company name, principal place of business, registered agent and registered office, and organizer information, then file online or mail the form in duplicate with the $150 fee. Series LLCs file Form LLC-5.5(S) with $400 instead.
- Write an operating agreement. Illinois does not collect this document, but it settles ownership percentages, profit splits, and exit rules before anyone is angry. Banks routinely ask for it when opening the company account.
- Request an EIN. The federal tax ID is free directly from the IRS and arrives immediately for most online applications. No third party can get it faster than you can.
- Diary the annual report. Form LLC-50.1 is due before the first day of your anniversary month each year, with the filing window opening 60 days ahead. The fee is $75, and Illinois adds a $100 penalty once you are 60 days past due. Full treatment on the annual requirements page.
Formation Through Us
Our service is $199 plus the $150 state fee, and it includes your first year of Illinois registered agent service. We prepare Form LLC-5.5, file it with the Department of Business Services, and hand you a finished company. Registered agent service renews at $99 per year afterward. Every number sits in one table on the fee breakdown page.