County, State, and Federal Business Registration

Business PlanningZoningBusiness LicensingPermittingAdditional Requirements

Before you establish a business, please consult with a Corporate/Business Law Attorney or Certified Public Accountant (CPA), who specializes in your industry, for advice about what type of business entity will meet your business needs and what your legal obligations will be. The type of business entity you choose will depend on three primary factors: liability, taxation and record-keeping. Additional information may also be obtained from the U.S. Small Business Administration (SBA) or SCORE Chicago.

Once you have consulted with a licensed business formation professional, and determined the most appropriate business entity for your needs, then you, or your licensed representative, must register your business entity with the proper government agency:

  • Sole Proprietors and General Partnerships, operating under an assumed name, must register with the Cook County Clerk's Office.
  • All other business entity types (i.e. Limited Partnership (LP), Limited Liability Partnership (LLP), Limited Liability Corporation (LLC), Corporation, or Not-for-Profit Corporation (NFP)) must register with the Illinois Secretary of State.

Accordingly, you, or your licensed representative, must also register for your business taxes with the U.S. Internal Revenue Service (IRS) and Illinois Department of Revenue (IDOR). The City of Chicago business tax registration is part of the business license application process. For additional information about business and tax registration, please review the chart below:

JurisdictionDescriptionContact
Cook County Assumed Business Name Registration
The Clerk's Office registers business names known as "assumed names" for new businesses in accordance with Illinois law. An assumed name is issued to any business entity that uses a name other than the name(s) of the individual(s) who own or operate the business. For example, a business called "John Jones, P.C." (i.e. owner's full name and title) does not have to file an assumed name, but "Jones Wrecking" does.

50 W. Washington St.
West Concourse Level
Suite 114
Chicago, IL
312.603.7790
State of Illinois
Register with the Secretary of State
If you plan to do business as a legal business entity in Illinois, regardless if you are based in Illinois or not, you will need to register with the Illinois Secretary of State.
50 W. Washington St.
West Concourse Level
Suite 1240
Chicago, IL
312.793.3380
Obtain an Illinois Department of Revenue (IDOR) Account ID Number (Formerly Illinois Business Tax Number – IBT)
You must register with IDOR if you conduct business in Illinois, or with Illinois customers. This includes sole proprietors (individual or husband/wife), and all legal business entities, including exempt organizations, who plan to hire employees, buy or sell products wholesale or retail, or manufacture goods.

100 W. Randolph St.
Chicago, IL
800.732.8866
US Government Obtain an Employer Identification Number (EIN)
An Employer Identification Number (EIN) is also known as a Federal Tax Identification Number, and is used to identify a legal business entity. Businesses are required to obtain an EIN to file and pay any federal tax obligation. You may register for an EIN with the United States Internal Revenue Service (IRS).

IRS Guide to Starting a Business
Find links to basic federal tax information for people who are starting a business, as well as information to assist in making basic business decisions. The list should not be construed as all-inclusive. Other steps may be appropriate for your specific type of business.
230 S. Dearborn St.
Chicago, IL
800.829.4933

When your business is up and running, visit our Tax Information section to learn about how to file your taxes, and see common City and County taxes for small businesses.

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