How to Start an LLC in Illinois: A Step-by-Step Guide (2027)

How to Start an LLC in Illinois (Quick Answer)

To start an LLC in Illinois, file the Articles of Organization (Form LLC-5.5) with the Illinois Secretary of State's Department of Business Services, and pay the $150 state filing fee. Once the state approves it, your LLC legally exists, and from then on it files a $75 Annual Report before the first day of its anniversary month each year.

First-year cost: $150 if you file the Articles of Organization yourself. If you are not based in Illinois, add a registered-agent service, commonly $35 to $300 a year, plus an optional $25 name reservation.

Illinois charges a flat 4.95% state income tax on top of a $75 annual report every LLC has to file, and neither cost makes sense unless the business is actually doing something in the state. Founders forming purely for a mailing address or a brand-name effect are paying for infrastructure they won't use.

Where Illinois earns its keep is logistics: it's the only state served by all seven Class I freight railroads, plus O'Hare, one of the busiest cargo airports on earth. Here's what forming an LLC there actually involves, step by step.

TL;DR

• Illinois fits operators, not shell entities: the 4.95% income tax and $75 annual report only pay off if the LLC has real operations, employees, or customers in the state.
• Step 1, name: confirm your LLC name is available with the Illinois Secretary of State, and put a hold on it if you're still lining up the rest of the paperwork before filing.
• Step 2, registered agent: you need a physical Illinois street address, no PO box, and you must designate it as commercial or non-commercial on the filing.
• Step 3, Articles of Organization: Form LLC-5.5 costs $150 ($400 for a Series LLC) and typically processes in 5 to 10 business days online.
• Step 4, EIN without an SSN: the IRS online tool needs an SSN or ITIN, so founders without one apply by phone, fax, or mail on Form SS-4.
• Step 5, operating agreement: not filed with the state, but this internal document backs up your liability protection by spelling out ownership and how the LLC is run.
• Step 6, state taxes and licenses: register with the Illinois Department of Revenue if you'll collect sales tax or have employees, then check for any local or industry-specific licenses your business needs.
• Step 7, Form 5472: a 25%+ foreign-owned single-member LLC must file this every year, even at zero revenue, or risk a $25,000 minimum penalty.
• Step 8, annual compliance: Illinois requires a $75 Annual Report before your LLC's anniversary month each year, with a $100 penalty if it's more than 60 days late.
• Common mistakes: missing the annual report's 60-day cure window and treating the EIN as the finish line are two of the costliest.

Why Form Your LLC in Illinois?

Illinois makes the most sense for businesses that actually move goods. It's the only state served by all seven Class I railroads, and Chicago's O'Hare International Airport ranks among the world's busiest cargo hubs.

That combination matters for import/export operations, distribution companies, and manufacturers coordinating a multi-state supply chain. A digital-only or holding-company setup won't use any of that infrastructure, and it will still pay the 4.95% income tax and $75 annual report regardless.

Illinois isn't a formation haven the way Delaware or Wyoming can be. Foreign qualification works the standard way here: it's an operating-state choice, not a low-cost or no-tax base to form in and then operate elsewhere from.

That distinction matters most for founders comparing states on reputation alone. A logistics or distribution business that will actually route freight through Chicago rail yards or O'Hare cargo terminals gets real value from being registered where it operates. A SaaS company with no physical footprint in Illinois generally won't.

Step 1: Choose and Reserve Your LLC Name

Your LLC's name needs a designator like "LLC" or "Limited Liability Company," and it must be distinguishable from names already on file with the Illinois Secretary of State.

• Search first. The Secretary of State's business name database lets you check availability before you file anything.
• Reserve it if needed. Form LLC-1.15 reserves a name for 90 days for a $25 fee.
• Reservation is optional. You don't have to reserve a name to form your LLC; you can file Form LLC-5.5 directly if the name's already available.
• No publication step. Illinois has no requirement to publish your LLC formation in a newspaper. The only publication provision in Illinois's LLC Act is an optional creditor-notice publication after dissolution, unrelated to forming the LLC.

Step 2: Appoint a Registered Agent

Every Illinois LLC needs a registered agent with a physical street address in the state, available during normal business hours to accept legal notices and state correspondence. A PO box doesn't qualify.

• Designate commercial or non-commercial. Illinois's filing form requires you to specify which type of registered agent you're using.
• A founder without an Illinois address typically needs a commercial registered agent service to satisfy this requirement.
• Business hours matter. The agent has to be reachable during standard hours, not just listed on paper.

Skipping a real registered agent for a friend's address or an unstaffed office can put the LLC out of good standing with the state.

Step 3: File Your Articles of Organization (Form LLC-5.5)

This is the filing that legally creates your Illinois LLC. It's filed with the Illinois Secretary of State's Department of Business Services.

• Filing fee: $150 for a standard LLC, $400 if you're filing a Series LLC (Form LLC-5.5(S)).
• Processing time: roughly 5 to 10 business days for online filings; paper or mail filings typically take longer.
• Expedited option: a $100 fee adds 24-hour processing on business days.
• What it lists: the LLC's name, registered agent and address, and other basic organizational details.

Once the state approves this filing, your LLC legally exists, and the clock starts on the federal and Illinois compliance obligations covered below.

Step 4: Get an EIN, Even Without an SSN

Most founders apply for their EIN online and get it in minutes. Founders without a Social Security Number or an ITIN can't use that tool and have to apply another way.

An Employer Identification Number (EIN) is what the IRS uses to identify your LLC for tax purposes, and it's free directly from the IRS either way. Founders without an SSN or ITIN use Form SS-4 by phone, fax, or mail instead.

The manual route's wait mostly depends on volume and whether the responsible-party details are filled out correctly the first time. A rejected submission means starting the wait over.

Step 5: Draft an Operating Agreement

An operating agreement is an internal document that spells out ownership percentages, member roles, and how the LLC is run day to day. Illinois doesn't require you to file it with the state, and it isn't a public record.

• It backs up your liability shield. Banks, investors, and courts can look at whether the LLC operates as a genuinely separate entity, not just a name on a filing, and a written operating agreement is part of that evidence.
• Single-member LLCs benefit too. Even with one owner, an operating agreement documents that the business is run separately from its owner's personal finances.
• Multi-member LLCs need it more. Without one, disputes over ownership splits, profit distributions, or what happens if a member leaves default to Illinois's general LLC statute rather than terms you chose yourself.

Open a US Business Bank Account

Once your Articles of Organization are approved and the EIN has arrived, open a dedicated business bank account before the LLC moves any money at all.

• Bring the paperwork. Banks typically ask for the approved Articles of Organization, your EIN confirmation letter from the IRS, and an operating agreement, even an internal one Illinois never sees.
• Keep funds separate from day one. Mixing personal and business money is one of the fastest ways to undermine the liability protection an LLC is supposed to provide, and it makes every later bookkeeping cleanup harder.
• Non-US founders should expect extra verification. Some banks want an in-person visit or additional identity documents before opening an account without a US-based owner present, so confirm a specific bank's requirements before counting on a fully remote setup.

The Illinois Secretary of State has no role in this step, but skipping it, or putting it off until revenue starts, is one of the more common gaps founders leave in an otherwise complete filing.

Step 6: Register for State Taxes and Business Licenses

Beyond the LLC formation filing itself, most businesses need to register separately for the taxes and licenses that apply to what they actually do.

• Register with the Illinois Department of Revenue if your LLC will collect sales tax, withhold employee payroll taxes, or owes other state-level business taxes.
• Check for local licenses and permits. Depending on your city, county, and industry, you may need additional registrations beyond what the state requires, such as a local business license or an industry-specific permit.
• Requirements vary by business type. A retail storefront, a food business, and a professional service firm each face different licensing rules, so confirm what applies to your specific operation before you open your doors.

Step 7: File Form 5472 if the LLC Is Foreign-Owned

Foreign ownership brings a filing obligation Illinois itself has no say in. Once a single-member LLC crosses the 25% foreign-ownership mark, the IRS expects a Form 5472 every single year, and an empty bank account doesn't excuse you from it. Nothing about the requirement originates in Springfield; it rides on top of whatever your Illinois LLC is already doing.

• A pro forma Form 1120 tags along. The IRS won't accept the 5472 on its own; it needs this placeholder corporate return attached.
• The form documents the money trail, capital you put in, payments for services, any other transaction flowing between the LLC and its foreign owner.
• Inactivity isn't an out. An LLC sitting idle for the year still owes the filing if it meets the ownership test.

Note: miss it or file it late and the IRS's own guidance puts the floor at $25,000 per form, per year, whether or not the LLC brought in a dollar.

Step 8: Handle Illinois's Ongoing Compliance

Illinois LLCs face two recurring obligations once formed: the state's Annual Report and state income tax on the LLC's earnings.

The Annual Report Deadline Is Easy to Miss

Illinois requires Form LLC-50.1, the Annual Report, every year.

• Fee: $75 for regular filing (an additional $50 if you want it expedited).
• Due date: before the first day of your LLC's anniversary month each year. You can file up to 60 days early.
• Late penalty: $100 if not filed within 60 days of the due date, and continued failure to file risks administrative dissolution.

Illinois Taxes LLC Income at a Flat Rate

Illinois imposes a flat 4.95% state income tax on pass-through income, reported on the owner's personal return for most LLCs. This is a real, ongoing cost compared to no-income-tax states, and it's one more reason forming here should track where the business actually operates.

Illinois also offers a Pass-Through Entity (PTE) Tax election at the same 4.95% rate, with an offsetting credit for owners. This election is now permanent after a previously scheduled 2026 sunset was repealed. It only applies to entities structured as partnerships, so a single-member LLC, which has no separate owner-level entity to elect on behalf of, isn't eligible.

Illinois LLC Costs Breakdown

Here is what forming and maintaining an Illinois LLC actually costs, using the figures covered in the steps above. Optional line items are marked as such, so you can see the required minimum separately from the extras.

How Long Does It Take to Form an LLC in Illinois?

The state filing is the first clock to watch. Illinois typically processes an online Form LLC-5.5 in roughly 5 to 10 business days, and paper or mail filings usually take longer. If the timeline is tight, a $100 expedite fee adds 24-hour processing on business days.

The EIN comes next, and it is where timelines split. Founders with an SSN or ITIN apply online and have the number in minutes. Founders without either file Form SS-4 by phone, fax, or mail, which runs from same-day to several weeks depending on IRS volume.

Then comes the bank account, which cannot start until the approved Articles of Organization and the EIN letter are both in hand. Plan the state filing and the EIN as sequential rather than parallel, and leave room for bank verification on top if no owner is US-based.

Common Mistakes to Avoid

• Missing the annual report's 60-day cure window: the $100 penalty hits once you're more than 60 days past the due date, and continued neglect risks administrative dissolution.
• Treating the EIN as the finish line: for a foreign-owned LLC, the EIN is closer to the starting gun on an annual filing obligation than the end of the process.
• Assuming a quiet bank account means no filing: Form 5472 comes due based on ownership structure, not on whether the LLC has earned a dollar.
• Using a home or unstaffed address as the registered agent: it can put the LLC out of good standing and exposes a personal address on public record.
• Forming in Illinois without an actual Illinois presence: the income tax and annual report are real costs that only make sense with real operations there.

How FinStackk Helps

FinStackk is an accounting and tax compliance platform for U.S. businesses, helping you go from incorporation to ongoing accounting, tax, and compliance, all in one place.

Getting the Form LLC-5.5 filing right, then lining up an EIN and a registered agent, is exactly the work Fin-Start takes off your plate.

Once your Illinois LLC exists, Fin-Tax keeps ongoing filings, including the Annual Report and Form 5472, on a proactive deadline calendar instead of leaving you to track them yourself. Book a free demo to see both in action.

FAQ

Does Illinois tax LLC income, and how much?

Yes. Illinois applies a flat 4.95% state income tax on pass-through income, typically reported on the LLC owner's personal return. Illinois also offers a Pass-Through Entity Tax election at the same rate for partnership-structured entities, now a permanent option, though a single-member LLC isn't eligible for it. Consult a tax professional to confirm how this applies to your specific structure.

What happens if I miss the Illinois Annual Report deadline?

Illinois gives LLCs a 60-day window past the due date before assessing a $100 late penalty on top of the $75 filing fee. Continued failure to file can lead to administrative dissolution of the LLC. The report is due before the first day of your LLC's anniversary month, and you can file up to 60 days ahead of that date.

Do I need a physical presence in Illinois to form an LLC there?

No, forming the LLC itself doesn't require you to be physically present. You still need a registered agent with a real Illinois street address, which is usually a paid service if you don't have one yourself. Given the ongoing income tax and annual report costs, Illinois generally makes the most sense when the business will have actual operations, employees, or customers in the state.

Do I need an operating agreement for an Illinois LLC?

Illinois does not require you to file one with the state, and it never becomes a public record. You still want one.

Banks commonly ask to see an operating agreement when you open a business account, and it is part of the evidence that the LLC runs as a genuinely separate entity rather than a name on a filing.

It matters most for multi-member LLCs. Without a written agreement, disputes over ownership splits, profit distributions, or what happens when a member leaves default to Illinois's general LLC statute instead of terms you chose. Single-member LLCs benefit too, since the document helps show the business is run separately from its owner's personal finances.

Can a non-US resident start an LLC in Illinois?

Yes. Illinois sets no residency or citizenship requirement to own an Illinois LLC. You'll still need a registered agent with a physical Illinois street address, which usually means a paid service if you're not in the state. Because you won't have an SSN, you apply for your EIN on Form SS-4 by phone, fax, or mail instead of the online tool. If your LLC is single-member and 25% or more foreign-owned, you also file Form 5472 with the IRS every year, even at zero revenue, or risk a $25,000 minimum penalty.

What are the annual filing requirements for a single-member LLC in Illinois?

Every Illinois LLC, including a single-member one, files Form LLC-50.1, the Annual Report, before the first day of its anniversary month each year, with a $75 filing fee. Illinois gives a 60-day window past the due date before a $100 late penalty applies, and continued failure to file risks administrative dissolution. A single-member LLC that is 25% or more foreign-owned also has a federal obligation: Form 5472, filed yearly with the IRS even in a year with no revenue, or the $25,000 minimum penalty applies.

Does an Illinois LLC pay income tax?

Yes. Illinois applies a flat 4.95% state income tax on pass-through income, typically reported on the LLC owner's personal return. Illinois also offers a Pass-Through Entity Tax election at the same 4.95% rate, but that election is only available to partnership-structured entities, so a single-member LLC isn't eligible for it. This is a real, ongoing cost a no-income-tax state wouldn't charge, which is why forming in Illinois makes the most sense when the business actually operates there.