How to start an LLC in Illinois

Check the name is free

Search on Business Entity Search. Searching the database by business name shows existing corporations and LLCs, and a 'no records found' result means the name may be available; this is only a preliminary check, because the Department of Business Services makes the final call when a name reservation or the Articles of Organization are filed.

Name ending

Limited Liability Company, L.L.C. or LLC (L3C for a low-profit LLC; PLLC, P.L.L.C. or Professional Limited Liability Company for a professional LLC)

Reserving

A name can be reserved for 90 days for $25 on Form LLC-1.15, renewable by filing again; the $25 does not count toward the formation fee.

Words to avoid or that need permission:

• Corporation, Corp., Incorporated, Inc., Ltd., Co., Limited Partnership and L.P. are banned 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 complying with the Corporate Fiduciary Act (and an LLC that accepts and executes trusts must use 'trust')
• no words implying insurance, assurance or banking business

Also worth knowing:

• The name must be distinguishable on the Secretary of State's records from other LLCs, admitted foreign LLCs, corporations, assumed names and reserved names; adding words like 'limited', 'liability' or 'company', articles, or a plural does not make a name distinguishable.
• Only English letters, Arabic or Roman numerals and symbols the office can reproduce are allowed.

Choose a registered agent

Can it be you?

Yes: an individual who lives in Illinois can serve, and the agent may be (but need not be) an organizer, manager, member or employee unless the articles or operating agreement say otherwise; otherwise use an entity authorized to do business in Illinois.

Address

The registered office must be in Illinois at a street or road address (or rural route and box number), the same as the agent's business office; a P.O. box alone or a c/o address is not accepted.

Their consent

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 act.

• All correspondence from the Secretary of State, including the pre-filled annual report notice, is mailed to the registered agent at the registered office.
• An agent's resignation takes effect no sooner than 30 days after filing, and the LLC must put a new agent on record within 60 days of the resignation notice.
• Failing to keep a registered agent and office eventually leads to involuntary dissolution.

File the Articles of Organization (Form LLC-5.5)

File online at Secretary of State’s online LLC filing. Fee: $150 (online card payments also carry a payment processor fee whose amount is not published).

The form asks for:

• LLC name
• Principal place of business where records are kept (no P.O. box alone or c/o)
• Effective date (filing date or a later date up to 60 days ahead)
• Registered agent's name and Illinois registered office address
• Purpose (standard 'any lawful business' wording, or specific purposes)
• Dissolution date, only if the operating agreement sets one
• Optional other provisions for internal affairs
• Names and business addresses of all managers and any member with manager authority
• Organizer names, addresses and signatures

What is different about Illinois’s form:

• The articles must list the names and business addresses of the managers, or of the members who have management authority, which most states do not ask for.
• Organizers sign under penalties of perjury that the articles are true, correct and complete.
• The online route is only for LLCs that are not formed elsewhere and do not need a specific purpose or special provisions (for example professional LLCs, which must state their specific professional service).
• Paper filings must be submitted in duplicate.

On 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, and paper filings can only be expedited by asking in person in Springfield or Chicago.

Wait for approval, or pay to go faster

10 business days for the $150 online filing; confirmation is emailed once the Department of Business Services has examined and approved the document.

The Secretary of State does not publish a standard time for mailed paper filings.

Do what comes after filing

Approval is the start. Get the LLC’s EIN, free from the IRS, then work through what Illinois expects next:

• File the annual report (Form LLC-50.1)Before the first day of the month the LLC was formed, every year from the year after formation · $75

  A pre-filled report goes to the registered agent about 45 days before the due date and most can be filed online. After 60 days late there is a $100 penalty, and after 120 days of delinquency the LLC is administratively dissolved.

• Register with the Illinois Department of Revenue (if selling taxable goods or services, or hiring)Before making purchases or sales, or hiring an employee

  Register through MyTax Illinois ('Register a New Business (Form REG-1)'), which takes about one to two business days online; a mailed REG-1 takes several weeks. This sets up accounts such as sales tax (Retailers' Occupation Tax) and employee income tax withholding.

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

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

• Personal Property Replacement Tax return (LLCs taxed as partnerships or S corporations)Partnerships (Form IL-1065): 15th day of the 4th month after the tax year ends, automatic 6-month extension. S corporations (Form IL-1120-ST): 15th day of the 3rd month, 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) and pays replacement tax on its Illinois income, while members pay income tax on their own returns; a single-member LLC treated as disregarded has no Illinois income tax filing of its own.

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

  The state's 2026 starting-a-business handbook lists general business licenses only as a local requirement (city, village or county, and a City of Chicago Business License for most types of business in Chicago); state licenses depend on the profession or industry, for example through IDFPR.