How to start an LLC in Illinois

Check your business name is free

Search for your name on Business Entity Search. Search the state's database by business name to see existing corporations and LLCs. If it says 'no records found', the name may be available. This is only a first check. The Department of Business Services makes the final decision when you file a name reservation or your Articles of Organization (the form that sets up your LLC).

Your name must end with

Limited Liability Company, L.L.C. or LLC. A low-profit LLC uses L3C. A professional LLC uses PLLC, P.L.L.C. or Professional Limited Liability Company.

Holding a name

You can reserve a name for 90 days for $25 on Form LLC-1.15. To renew, file again. The $25 does not count toward the formation fee.

Words you can’t use, or need permission to use:

• Corporation, Corp., Incorporated, Inc., Ltd., Co., Limited Partnership and L.P. are not allowed in an LLC name
• bank, banker and banking only with a signed permission statement from the Secretary of Financial and Professional Regulation
• trust, trustee and fiduciary only after you follow the Corporate Fiduciary Act. An LLC that acts as a trustee (holding and managing money or property for others) must use 'trust'
• no words that suggest an insurance, assurance or banking business

Also worth knowing:

• Your name must be clearly different from names on the Secretary of State's records. These include other LLCs, foreign LLCs (formed in another state) allowed to work in Illinois, corporations, assumed names (trading names) and reserved names. Adding 'limited', 'liability' or 'company', words like 'the' or 'a', or a plural does not make a name different enough.
• You can only use English letters, ordinary digits, Roman numerals and symbols the office can reproduce.

Choose your registered agent

Every LLC needs a registered agent: a person or company with an address in Illinois who receives legal papers and official letters for it.

Can you do it yourself?

Yes, if you live in Illinois. Otherwise, use a business allowed to operate in Illinois. Your registered agent can be an organizer, manager, owner (member) or employee, but does not have to be. Your Articles or operating agreement (the owners' agreement on how the LLC is run) can set a different rule.

Address rules

The registered office (the official address where your agent receives legal papers) must be a street or road address in Illinois (or a rural route and box number). It must be the same as the agent's business office. A P.O. box on its own or a c/o (care of) address is not accepted.

Do they need to agree?

No. The agent does not sign or file a consent with the Articles. But the Secretary of State says to name someone only after they have agreed to be your agent.

• The Secretary of State mails all letters, including the pre-filled annual report notice, to the registered agent at the registered office.
• If your agent resigns, this takes effect at least 30 days after they file. Your LLC must register a new agent within 60 days of the resignation notice.
• If your LLC does not keep a registered agent and office, the state will in time close it down.

File the form that creates your LLC

The form is called the Articles of Organization (Form LLC-5.5). File it online at Secretary of State’s online LLC filing. The fee: $150 (paying by card online also adds a processing fee; the amount is not published)

You’ll be asked for:

• LLC name
• Main business address where records are kept (not a P.O. box on its own or a c/o address)
• Effective date (when your LLC starts: the filing date, or a later date up to 60 days ahead)
• Registered agent's name and Illinois registered office address
• Purpose (the standard 'any lawful business' wording, or specific purposes)
• End date for the LLC (dissolution date), only if your operating agreement (the owners' agreement on how the LLC is run) sets one
• Optional other rules on how the LLC is run
• Names and business addresses of all managers and any owner (member) with power to manage
• Names, addresses and signatures of the organizers (the people who file the form)

Good to know about the Illinois form:

• The Articles must list the names and business addresses of the managers, or of the owners (members) who have power to manage. Most states do not ask for this.
• Organizers sign, under penalty of perjury (lying on a legal paper), that the Articles are true, correct and complete.
• You can only file online if your LLC was not formed outside Illinois and does not need a specific purpose or special rules. For example, a professional LLC must state its specific professional service, so it cannot file online.
• Paper filings must be sent in two copies.

Prefer paper? Yes. Mail two identical copies of Form LLC-5.5 (at least one original) with the $150 fee to the Department of Business Services, Limited Liability Division, in Springfield. Cash is not accepted. Paper filings can only be expedited (faster, for an extra fee) if you ask in person in Springfield or Chicago.

Wait for approval (or pay to speed it up)

10 business days for the $150 online filing. You get a confirmation email once the Department of Business Services has checked and approved it.

The Secretary of State does not publish a usual time for paper filings sent by mail.

After approval: what to do next

Once your LLC is approved, get its EIN (the business tax number), free from the IRS. Then work through what Illinois asks for next:

• File the annual report (Form LLC-50.1)Before the first day of the month your LLC was formed in, every year starting the year after you form · $75

  A pre-filled report goes to your registered agent about 45 days before the due date. Most can be filed online. After 60 days late, there is a $100 penalty. The state also sends a late notice (notice of delinquency). If you still have not filed 120 days after that notice, the state closes your LLC down.

• Register with the Illinois Department of Revenue (if you sell taxable goods or services, or hire staff)Before you make purchases or sales, or hire an employee

  Register through MyTax Illinois ('Register a New Business (Form REG-1)'). Online, this takes about one to two business days. A mailed REG-1 takes several weeks. This sets up accounts such as sales tax (Retailers' Occupation Tax) and income tax held back from employees' pay.

• Register with IDES for unemployment insurance (if you have employees)Within 30 days of starting up

  New employers register with the Illinois Department of Employment Security (IDES) through MyTax Illinois or by filing Form REG-UI-1.

• Personal Property Replacement Tax return (for LLCs taxed as partnerships or S corporations)Partnerships (Form IL-1065): 15th day of the 4th month after the tax year ends, with an automatic 6-month extension. S corporations (Form IL-1120-ST): 15th day of the 3rd month, with an automatic 7-month extension. · 1.5% of Illinois net income (2.5% if taxed as a C corporation)

  An LLC taxed as a partnership files Form IL-1065 (an S corporation files IL-1120-ST). With both of these federal tax setups, the owners (members) pay income tax on the profit on their own returns. The LLC itself pays replacement tax on its Illinois income. A one-owner LLC taxed as part of its owner ('disregarded') has no Illinois income tax filing of its own.

• Local and professional licenses (no general state license listed)Before you open · Varies

  The state's 2026 starting-a-business handbook lists general business licenses only as a local requirement. That means your city, village or county, plus a City of Chicago Business License for most types of business in Chicago. State licenses depend on your profession or industry, for example through IDFPR (the Illinois Department of Financial and Professional Regulation).