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We can help you search for the right business name, register your LLC with the Illinois Secretary of State (SOS), and more. We’ve got all the information you need on conducting an Illinois business search, LLC naming rules, using an assumed name, and registering your business.


General Rules for LLC Names

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

Your LLC Name Must Be Unique

The business name you've chosen cannot be used by any other LLC or corporation in the State of Illinois. This is why it's imperative to perform an IL SOS business search before you begin the filing process.

Your LLC Name Must Not Be Confusable with Another Business Name

It’s not enough for your LLC name to be unique. It also cannot be similar to the name of another corporation or LLC in Illinois. In addition, 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, such as “A,” “An,” or “The.”
  • The conjunction "And," or “&."
  • The singular, plural or possessive forms of words
  • Abbreviations, punctuation, symbols, fonts, typefaces, etc.
Your LLC Name Must Contain Certain Words

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

Your LLC Name May Have Other General Restrictions

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

  • Are too similar to the name of a federal or state 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 International Olympic Committee
  • Imply a purpose that would be illegal for your business to carry out

Specific Rules for Illinois Business Names

In addition to the general rules listed above, Illinois has some specific business naming guidelines. You’ll need to follow them to appropriately name your business. For example, the name:


shall consist of letters of the English alphabet, Arabic or Roman numerals, or symbols capable of being readily reproduced by the Office of the Secretary of State.


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, such as "trust," "trustee," or "fiduciary," unless it has first complied with Section 1-9 of the Corporate Fiduciary Act (205 ILCS 620/1-9).


shall not contain any of the following terms: "Corporation," "Corp.," "Incorporated," "Inc.," "Ltd.," "Co.," "Limited Partnership" or "L.P."

How to Come Up with a Business Name

Giving your business the perfect name can be difficult. We’ve put together a complete guide to choosing the right business name, but essentially, you'll want to choose a name that will:

Best demonstrate your product or services

Be unique from any other business in the state

Attract customers

Be memorable enough to stand out

Need help coming up with business name ideas? Try our free Business Name Generator.

Illinois Business Search

Once you’ve found a name you like, you’ll need to perform an Illinois entity search to make sure another business isn’t already using it.

Incfile offers a fast, simple and convenient tool to research the business name you want. The Illinois SOS also has a tool that lets you search the registry of LLCs and corporations to see whether another business is already using your name.

Find out whether your preferred business name is available in Illinois with Incfile’s free tool

Trademarks and Service Marks

You must be careful that your Illinois LLC name doesn’t infringe on the trademark or service mark that another business holds. The easiest way to ensure compliance is to complete a trademark search through Incfile. If no one else is using the trademark or service mark, you can even register it yourself.

Make sure your business is starting off on the right foot when it comes to intellectual property.

Let Incfile run a trademark search for you.


Illinois DBA or Assumed Name

You may do business as a different name from your legal LLC name. In some states, this is called a DBA (doing business as) name. In Illinois, it’s known as an assumed name. You may choose to use an assumed 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 Shoreline Tourism and Leisure. You should file an assumed name to let the Illinois SOS know. In Illinois, you do that with the Application to Adopt, Change, Cancel or Renew an Assumed Name, or you can have Incfile do it on your behalf through our Trade Name service.

Note: A trade name is not the same as a trademark.

Register and manage a DBA or assumed name through our easy-to-use DBA Name service

Register Your Business Name with the Illinois SOS

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


If you don’t want to form your LLC right now, you can reserve the business name. You’ll need to complete an Application to Reserve a Name and file it with the Illinois SOS. Once you do so, your name will be reserved for 90 days. You don’t need to reserve a name if you’re forming your business right away.


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

Incfile can handle all your formation paperwork with the State of Illinois for you — and we’ll do it for free!

Form an LLC in Illinois for $0 + State Fee ($150)

FAQs About Illinois Business Names

How Do I Search for My Illinois Business Name?

Just go to the free Business Name Search tool and enter your proposed business name. You can also perform an Illinois Secretary of State business search of the state's registry, which will tell you whether there are any corporations or LLCs with that name in the state.

Are There Any Rules for Naming My Business in Illinois?

Yes. Most LLCs will be bound by general rules applicable to all LLCs and specific rules to 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. You can conduct business under an assumed name. Details are above.

Can I Reserve a Name for My LLC in Illinois?

Yes. If you don’t want to start your business immediately, the Illinois SOS allows you to reserve a name. Details are above. But if you’re ready to start your business now, this step isn’t necessary.

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