Updated October 12,2020:

An Illinois Secretary of State Identification Number allows you to do business within the state of Illinois, hire employees, and file taxes.

Federal Tax ID Number: Overview

A Federal tax ID number, also known as an employer identification number (EIN), is issued to businesses by the IRS. It's also known as a Tax ID Number (TIN). An EIN is like a Social Security Number for businesses. Getting an EIN doesn't mean a business has to have employees; rather, the EIN is used for doing things that include:

  • Opening a business checking account
  • Obtaining a merchant services account for processing credit cards
  • Handling payroll and taxes for employees
  • Getting a line of credit for business
  • Getting business credit cards

But before getting an EIN, you should wait for the Secretary of State to approve your LLC.

Corporation and LLC Search

When seeking to register an LLC, an applicant has to perform a search of the LLC or Corporation Database by name or file number. You should keep in mind that the name you propose has to be distinguishable from an existing corporation or LLC name already filed. If the name you are searching for is not registered, the search will return no records found. That means the requested LLC or corporations name is able to be used.

It's important to understand that checking the database is a preliminary step, and the final determination of name availability for your desired name is by the Secretary of State's office. Compliance with Illinois statues is also checked at this time. You also have the option to email or call the Corporate Name Availability Request office at 217-782-6961. LLCs can call 217-524-8008 to find out if their desired name is already registered.

The Department of Business Services Database

The Department of Business Services database includes information on names for business entities that include:

  • Corporations
  • Not-For-Profit Corporations
  • Limited Partnerships
  • Limited Liability Companies
  • Limited Liability Partnerships

Information obtained from the database is available to the public for individual searches only. Users cannot access the database for the purpose of copying or downloading bulk searches of information.

How Do I Obtain an LLC Illinois State ID Number?

First, you start by forming an LLC in Illinois. This requires the filing of the Articles of Organization through the Illinois Secretary of State. You must also obtain a taxpayer identification from the Illinois Department of Revenue and certificate of registration. Getting an Illinois TIN requires filing a Business Registration Application through the Illinois Department of Revenue. 

Included in the Articles of Organization is the File Detail Report. This report includes information commonly requested on the company such as:

  • Exact name
  • Jurisdiction
  • Date of registration or formation in Illinois
  • The Registered Agent name
  • Duration
  • The Registered Office address

The corporation report also includes addresses and names of the secretary and president. It provides the final date an Annual Report was filed and indicates if the business is in good standing or not. 

The Illinois Department of Revenue accepts applications by mail or online. When applying online, go through the Illinois Business Gateway website or Form REG-1 if filing by mail. 

Complete the Illinois Business Registration Application and provide the company's FEIN, business name, primary and mailing business address. Indicate that the company is an LLC and the IRS's classification for federal tax purposes. Provide the number given to the business through the Illinois Secretary of State. Include the addresses and names of all members and managers. Then describe the main activity of the business and if it will have employees. Include appropriate forms for certain types of businesses.

Date and sign the application, then file it either online or by mail. File online through the My Tax Illinois website and follow the directions on the screen for submission. If filing by mail, the mailing address is:

Central Registration Division
Illinois Department of Revenue
PO Box 19476

There is no filing fee. 

It takes anywhere between six to eight weeks for an application to be processed by mail. You will then get your Certificate of Registration and taxpayer ID upon finalization of the paperwork. 

You must display the Certificate of Registration in a prominent location of the business so all who enter the business are able to view it. 

If you need help obtaining an Illinois Secre tary of State identification number, you can post your legal need on UpCounsel's marketplace. UpCounsel accepts only the top 5 percent of lawyers to its site. Lawyers on UpCounsel come from law schools such as Harvard Law and Yale Law and average 14 years of legal experience, including work with or on behalf of companies like Google, Menlo Ventures, and Airbnb.