How to Form an LLC in Illinois: Filing and Requirements (2025)

Starting an LLC in Illinois offers business owners liability protection and operational flexibility. Following the correct steps ensures your business remains compliant, your filings are accurate, and your internal structure is properly documented. This guide walks you through how to form an LLC in Illinois in 2025, covering key steps from selecting a name to registering with the Department of Revenue.

1. Choose Your LLC Name

Choosing a compliant and unique name is the first step. Illinois law requires that your LLC name:

• Include “Limited Liability Company,” “LLC,” or “L.L.C.”

• Be distinguishable from existing businesses in the state

• Avoid restricted terms like “Corporation,” “Inc.,” or “Bank”

Check name availability using the Illinois Secretary of State Business Entity Search. You may also reserve your desired name for 90 days by filing Form LLC-1.15 with a $25 fee, which ensures the name is secured while you prepare your formation documents.

2. Designate a Registered Agent

Every Illinois LLC must appoint a registered agent to receive legal and official correspondence. The agent must:

• Have a physical street address in Illinois (P.O. boxes are not allowed)

• Be an individual or a business authorized to operate in Illinois

• Accept service of process and state communications

3. File Articles of Organization

Filing the Articles of Organization (Form LLC-5.53) legally creates your LLC in Illinois. Filing options and fees include:

• Online filing: $150

• Mail filing: $200

The Articles require your LLC name, registered agent information, management structure (member-managed or manager-managed), business purpose, and organizer details. Optional expedited processing is available for an additional fee. Once approved, your LLC becomes a recognized legal entity, ready to operate.

4. Draft an Operating Agreement

While Illinois does not require an Operating Agreement, it is highly recommended. This document:

• Defines member ownership, management roles, and voting rights

• Outlines procedures for operations and dispute resolution

• Helps protect your limited liability status

Operating Agreements are particularly useful for opening business bank accounts and providing clarity in case of legal disputes. Keep your copy with business records; it does not need to be filed with the state.

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5. Obtain an EIN

An Employer Identification Number (EIN), also called a Federal Tax ID, is essential for tax reporting, hiring employees, and opening business bank accounts. Key points:

• Apply for free via the IRS website

• US residents with an SSN or ITIN can apply online

• Non-US residents must apply via mail or fax using IRS Form SS-4

Obtaining an EIN ensures that your LLC can operate legally and handle financial matters efficiently.

6. Register with the Illinois Department of Revenue

All Illinois LLCs must register with the Department of Revenue (DOR). Registration provides:

• A Certificate of Registration, which functions like a general business license

• A State Taxpayer ID, separate from your federal EIN

Both items are free and mandatory. Depending on your location, local business licenses or permits may also be required. Registering ensures compliance with Illinois tax laws and avoids potential penalties.

Summary

Forming an LLC in Illinois involves several critical steps: selecting a unique name, designating a registered agent, filing Articles of Organization, drafting an Operating Agreement, obtaining an EIN, and registering with the Department of Revenue. Following these steps actively protects your liability, ensures legal compliance, and lays a strong foundation for your business. By carefully managing each stage of the process, entrepreneurs can confidently start and operate their Illinois LLC in 2025.

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