Single-member or multi-member LLC?

Single-member LLCs are taxed as sole proprietorships by default; multi-member as partnerships. Both can elect S-corp or C-corp taxation. The operating agreement should reflect the actual capital and decision structure regardless.

Do I really need an operating agreement?

Yes — even for a single-member LLC. It documents the liability shield, capital contributions, and management structure. Banks, the IRS, and courts all expect to see one.

Should I form in Delaware or my home state?

If your business operates in one state, form there. Out-of-state formation requires foreign qualification (and double fees) wherever you actually operate. Delaware is meaningful mainly for VC-backed companies.

When should I elect S-corp taxation?

Generally once net profit reliably exceeds the owner's reasonable salary by $30,000–$50,000. Below that threshold, the payroll and accounting overhead outweighs the self-employment-tax savings.

Home/Legal Guides/LLC Formation/Illinois

ILLINOIS LEGAL GUIDE

How LLC Formation Works in Illinois

How to form an LLC — name reservation, articles of organization, operating agreement, EIN, and the ongoing compliance you should plan for.

Typical timeline

1 – 4 weeks to active LLC

Fastest path

Same day (expedited filing)

Filing fee

Varies by county

IL venue

State + county court

Overview

LLC Formation in Illinois, in plain English

A Limited Liability Company (LLC) is a state-chartered business entity that combines limited liability protection with pass-through taxation. It is the default choice for most small businesses, real estate holdings, and professional practices.

Formation is a state-level process, but every LLC also has federal tax filings, an operating agreement, and ongoing annual obligations. The right structure depends on members, capital, industry, and tax election (default partnership or S-corp).

What follows is the Illinois-specific version of the llc formation process — including the rules that most often surprise people, and the typical timeline and cost ranges you should plan for.

The Legal Process

Step-by-step: llc formation in Illinois

Each step below shows the typical Illinois sequence and how long it takes. Steps may overlap; complex cases add discovery and motion practice.

1
Choose a name & check availability
Same day
The name must include 'LLC' or 'Limited Liability Company' and be distinguishable from existing entities. Reserve the name if formation will take time.
2
Appoint a registered agent
Same day
Every state requires an in-state agent for service of process. Members may serve as their own agent or hire a commercial service.
3
File Articles of Organization
1–3 weeks (faster with expedited)
Filed with the Secretary of State. Includes name, address, agent, member/manager structure, and signature.
4
Draft an Operating Agreement
1–2 weeks
The internal contract that governs ownership %, capital contributions, distributions, voting, transfer restrictions, and dissolution. Required in some states.
5
Get an EIN
Same day
Federal Employer Identification Number from the IRS — required to open a bank account and hire employees. Free, immediate online.
6
Open a business bank account
1–2 weeks
Critical for maintaining the liability shield. Use the EIN, formation documents, and operating agreement.
7
Tax election (optional)
Within 75 days
File Form 2553 to elect S-corp taxation when it makes sense (typically once net profit exceeds reasonable salary).
8
Ongoing compliance
Annual
Annual reports, state franchise tax, registered agent renewal, separate books, and updated operating agreement when members change.

Costs

What llc formation costs in Illinois

DIY formation runs $50–$500 in state fees. Attorney-prepared formation with a custom operating agreement typically runs $1,000–$3,500.

State filing fee

$50 – $500

Varies widely by state

Registered agent (annual)

$0 – $300

Attorney formation (flat fee)

$1,000 – $3,500

Custom operating agreement

$500 – $1,500

Annual report / franchise tax

$0 – $800+/yr

Ranges are typical Illinois figures. Your matter's complexity, contested issues, and counsel's experience all move the number.

Attorney Recommendations

Verified Illinois Business Formation attorneys

Featured attorneys with active Illinois licenses and business formation practice experience. Each offers a consultation to discuss your matter.

Verified

Featured

Isabella U. Latham

4.5

Managing Partner · Ashford & Associates

Springfield, IL

Green Card LawBusiness Formation

31 yrs expConsult

All Illinois Business Formation attorneys Browse Illinois directory

FAQs

LLC Formation in Illinois — common questions

Single-member or multi-member LLC?: Single-member LLCs are taxed as sole proprietorships by default; multi-member as partnerships. Both can elect S-corp or C-corp taxation. The operating agreement should reflect the actual capital and decision structure regardless.
Do I really need an operating agreement?: Yes — even for a single-member LLC. It documents the liability shield, capital contributions, and management structure. Banks, the IRS, and courts all expect to see one.
Should I form in Delaware or my home state?: If your business operates in one state, form there. Out-of-state formation requires foreign qualification (and double fees) wherever you actually operate. Delaware is meaningful mainly for VC-backed companies.
When should I elect S-corp taxation?: Generally once net profit reliably exceeds the owner's reasonable salary by $30,000–$50,000. Below that threshold, the payroll and accounting overhead outweighs the self-employment-tax savings.

Keep reading

How LLC Formation Works in Illinois

LLC Formation in Illinois, in plain English

Step-by-step: llc formation in Illinois

Choose a name & check availability

Appoint a registered agent

File Articles of Organization

Draft an Operating Agreement

Get an EIN

Open a business bank account

Tax election (optional)

Ongoing compliance

What llc formation costs in Illinois

Verified Illinois Business Formation attorneys

Isabella U. Latham

LLC Formation in Illinois — common questions

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