How to Form an LLC in Illinois
Illinois sits in the middle on price: $150 to form, $75 a year to report. What makes Illinois different is precision. The annual report deadline, the $100 late penalty at 60 days, and dissolution at 120 days are all spelled out by the state, and all enforced.
Illinois at a glance
Filing fee: $150 for the Articles of Organization (Form LLC 5.5), filed with the Illinois Secretary of State. Recurring: An annual report every year, $75, due before your anniversary month, plus Illinois replacement tax on LLC income for most classifications. Registered agent: required, with a physical address in Illinois. Every figure on this page was checked against the Illinois Secretary of State's official site on November 7, 2026.
On this page
The Illinois filing steps
Check your name on the state's own search
Run the name through the Secretary of State's Business Entity Search and its name availability check before filing. Illinois requires the name to be distinguishable from existing entities and to include "Limited Liability Company," "LLC," or "L.L.C." The search is free and it is the database your filing is judged against.
Choose your registered agent
Illinois law is explicit: all LLCs must appoint and maintain a registered agent in Illinois. The agent is an individual who lives in Illinois or an entity authorized to do business here, and the registered office must be a street address (a P.O. box alone is not acceptable) that matches the agent's business office. Illinois mails a pre-filled annual report to your agent about 45 days before it is due, one more reason the agent's address has to be one that actually reaches you.
File the Articles of Organization with the Secretary of State
File the Articles of Organization (Form LLC 5.5) with the Secretary of State's Department of Business Services, online or by mail, for $150. Standard processing runs about ten business days. If you need it faster, 24-hour expedited service adds $100, for $250 total. Online payments also carry a processor fee. Save the stamped Articles; your bank will want them.
Get an EIN from the IRS
Free, online, and takes minutes once your Illinois filing is approved. Never pay a service for this. See EIN for an LLC for the walkthrough and the one IRS rule (a real person as responsible party) that surprises people.
Write your operating agreement
Illinois recognizes oral and written operating agreements, but a written one is what a bank, a court, or a departing partner will ask for. Write it, sign it, and keep it with the formation records. The state does not collect it.
Open the business bank account and handle licenses
Bring your approved formation document and EIN letter. Then check your city and county for a general business license and your industry for state permits. Illinois has no single state business license, but many professions are licensed through the Department of Financial and Professional Regulation, and Chicago and other municipalities run their own licensing. Check your city clerk and your industry regulator before opening.
Filing details that trip people up
- Illinois is the series LLC state. Form LLC 5.5(S) creates a series LLC for $400, letting one LLC hold multiple series with separate assets and liabilities. It is a specialist tool with real legal complexity. Most founders want the standard $150 form, and this guide assumes that.
- The expedited fee is the state's, and it is real. $100 extra buys 24-hour handling from the Secretary of State. Formation services sometimes relabel their own queue-jumping with similar words; know which one you are paying.
- No publication step. The Secretary of State's official organizing guide lists the formation and reporting steps for an Illinois LLC, and newspaper publication is not among them.
- Foreign LLCs pay the same $150. An out-of-state LLC applying for admission to transact business in Illinois (Form LLC 45.5) pays $150, then owes the same $75 annual report.
After your Illinois LLC is approved
Illinois compliance starts sooner than founders expect: your first annual report is due before the first day of your anniversary month in the following year, and the state will mail a pre-filled form to your registered agent about 45 days ahead. Get the EIN, open the bank account, and register for Illinois taxes with the Department of Revenue. How your LLC is classified federally decides which Illinois return it files, covered on the cost and report pages.
The full recurring picture for Illinois, with fees and due dates, is on the Illinois annual report and compliance page, and the money view is on the Illinois LLC cost page.
Illinois LLC questions
When exactly is the Illinois annual report due?
Before the first day of your anniversary month, every year. Formed September 15, your report is due before September 1 of the following year, and every year after. Full detail on the Illinois report page.
What if I file the annual report late?
Within 60 days of the due date, file as normal. Past 60 days, the state adds a $100 penalty and marks the company in penalty status. Past 120 days from delinquency, the LLC is administratively dissolved.
Does Illinois tax LLCs directly?
Illinois charges a Personal Property Replacement Tax at the entity level for most classifications: 1.5% of net Illinois income for an LLC taxed as a partnership. It is an income tax, not a flat fee, so a year with no Illinois income is a year with no replacement tax. The cost page breaks down who files what.
Does an Illinois LLC file a BOI report?
No. US-formed companies are exempt under the federal final rule of August 14, 2026. See the BOI tracker.
General Information Only
LLCForming publishes general information about forming and running an LLC. It is not legal, tax, or accounting advice, and it does not create an attorney or advisor relationship. Rules vary by state and by your situation. For a decision that matters, talk to a licensed attorney or tax professional in your state.