Whether you’re searching for the right Illinois business name or registering your LLC with the IL Secretary of State, we can help. We’ve got all the information you need on Illinois business entity searches, LLC naming rules, fictitious names and registering your business.

General Rules for LLC Names

These rules typically apply to all LLCs, no matter what state they are formed in.

Your LLC Business Name Must Be Unique

The business name you have chosen cannot be used by any other LLC or corporation in the state of Illinois. This is why you should check business name availability on the IL SOS website.

Your LLC Business Name Must Not Be Confusable with Another Business Name

It’s not enough for your IL LLC name to be unique. It also cannot be similar to the name of a corporation or LLC in Illinois. For example, you cannot use the following factors to say your name is different from the name of another business:

  • Suffixes, such as Corporation, Company, Incorporated, Incorporation, Limited, Corp., Co., Inc., Ltd., LLC, etc.
  • Definite articles like “A,” “And,” “An,” “&,” “The,” etc.
  • The singular, plural or possessive forms of a word
  • Abbreviations, punctuation, symbols, fonts, typefaces, etc.
Your LLC Business Name Must Contain Certain Words

All LLCs must have the words “Limited Liability Company,” “L.L.C.” or “LLC” in their name. These words should normally come at the end of the name.

Your LLC Business Name May Have Other General Restrictions

Most states will not allow you to form LLCs with names that:

  • Are very similar to the name of a federal or IL agency or organization (e.g., FBI, FDA, Illinois Comptroller, Illinois Police, Treasury, etc.)
  • Suggest affiliation with a federal or state agency or organization
  • Use the term “Olympic” or any terms that are trademarks of the Olympic organization
  • Imply a purpose that it would be illegal for your business to carry out

Specific Illinois Rules for Business Names

In addition to the general rules listed above, the Illinois Secretary of State has some specific business naming rules for your LLC. You will need to follow these rules if you want to name your IL business appropriately. Here are some direct quotes from the Illinois Secretary of State:


The name of the proposed limited liability company may not contain any word or phrase that indicates or implies that it is organized for the purposes of insurance, assurance or banking.


The limited liability company name may not contain any word or phrase that indicates or implies that it is authorized or empowered to be in the business of a corporate fiduciary unless otherwise permitted by the Secretary of Financial and Professional Regulation under Section 1-9 of the Corporate Fiduciary Act.


While the name of the limited liability company must contain the word "trust" if it is organized for the purpose of accepting and executing trusts, the words "trust," "trustee" or "fiduciary" may be used by a limited liability company only if it has first complied with Section 1-9 of the Corporate Fiduciary Act (205 ILCS 620/1-9).

Read more about naming regulations from the Illinois Secretary of State.

Coming up with a Great Business Name

The perfect business name can be elusive. We have a complete guide to choosing the right business name, but basically, you'll want to choose a name that will:

Appeal to your customers

Be memorable enough to stand out

Best represent your product or services

Not be used by another business

Need Help Coming up with Business Name Ideas?

Try Incfile’s free Business Name Generator.

Illinois Business Entity Searches

Once you have an idea of what business name you’d like to use, you’ll need to complete an Illinois business entity search. Incfile offers a fast, simple and convenient tool to look up your proposed business name. The Illinois SOS also has a tool that lets you search the register of IL LLCs and corporations to see if someone already has your desired business name.

The Illinois Secretary of State search tool lets you enter details and search for your IL LLC by the following fields:

  • Name
  • Keyword
  • Partial Word
  • File Number

If the business name is already used, that means it’s not available and you won’t be able to register it. Try searching for a different business name instead.

Find Out if Your Preferred Business Name Is Available in Illinois

With Incfile’s free tool.

DBA / Assumed Names for Illinois LLCs

You might choose to do business under a different name from your legal LLC name. In Illinois, doing business under a different name is known as an “Assumed Name.” You might choose to use a different name from your IL formal LLC name for a variety of reasons.

For example, your LLC might be called Illinois Great Lakes Holding Company LLC and you have a chain called Lake Illinois Tourism and Leisure. You should file an assumed name to let the Illinois Secretary of State know. In Illinois, you do that through the “Application to Adopt, Change, Cancel or Renew an Assumed Name” form (Form LLC-1.20), or you can have Incfile do it on your behalf through our Assumed Business Name service.

Register and Manage an Assumed Name or DBA Name

Through our easy-to-use service.

Register Your Business Name with the Illinois Secretary of State

Once you’ve searched for your Illinois business name, checked availability, followed the naming rules and decided whether you need an assumed business name, you can register your IL LLC name. There are a couple of ways to do this.


If you don’t want to form your Illinois LLC right now, you can reserve the business name with the Illinois Secretary of State. You will need to complete an LLC-1.15 “Application to Reserve a Name” form and file it with the IL SOS. You do not need to reserve a name if you are forming your business right away.


If you’re ready to start your Illinois LLC, you can formally file your Articles of Organization with the Illinois Secretary of State, or have Incfile do it for you.

Incfile Can Handle All Your Incorporation Paperwork with the State of Illinois for You—and We’ll Do It for Free!

Incorporate in Illinois for $0 + state fee ($154).

FAQs About Naming Your Illinois LLC

You’ll find plenty more insight and guidance on the other pages of this guide, including:

How Do I Search for My Illinois LLC Business Name?

Just go to the business name search tool and enter your proposed business name. You can search the register of the Illinois Secretary of State, which will tell you if there are any IL corporations or LLCs with that name.

Are There Any Rules on Naming My Illinois LLC?

Yes. Most LLCs will be bound by general rules (applicable to all LLCs) and specific rules (applicable in the state of Illinois). We’ve detailed these rules above.

Can I Do Business Under a Different Name Than My LLC Name in Illinois?

Yes. Known as “assumed names,” “fictitious names,” “doing business as names” or “trade names,” you can choose to conduct business under a different name. Details are above.

Can I Reserve a Name for My Illinois LLC?

Yes. The Illinois Secretary of State allows you to reserve a name if you don’t want to start your business immediately. Details are above. If you are ready to start your business now, you do not need to reserve a name.

Trademarks and Service Marks

You must be careful that your Illinois LLC name does not infringe on the trademark or service mark of another business. The easiest way to make sure your proposed business name does not infringe is to carry out a trademark search through Incfile. If it doesn’t infringe, you can even register it as a trademark yourself.

Make Sure Your Business Is Starting off on the Right Foot When It Comes to Intellectual Property

Have Incfile run a trademark search for you.

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