New Jurisdiction: Illinois (2,800,000 companies)

A win for open data advocacy: official company data from Illinois is now available in OpenCorporates.

The addition of over 2.8 million Illinois companies, including those incorporated in the third largest US city, Chicago, means that OpenCorporates now contains company information for all 50 US States (plus the District of Columbia) – exclusively collected from their official company registers.

As part of our mission to open up company data for all, we successfully made the case for the positive impacts of open company data on the Illinois business environment and on society – both locally and around the world. 

That’s why we’re proud Illinois took the progressive step last year to make its company information available as open data, legislating to overturn what were previously restrictive terms and conditions about its use. Along the way, we helped those crafting the bill to maximise the positive impact of the open company data.

Representative Will Guzzardi, a member of the Illinois House of Representatives whose support was instrumental in the bill to open up the data passing, explained in an interview with us about the poor state of access to their company data: “…people had to pay to access our data and could face criminal charges for scraping it, it sounds so strange”. 

Senator John Connor, who was also vital to the effort, added: “We were forcing companies to go through hurdles or unusual methods to access what should have been openly and transparently available information”.

Adding the more than 2.8 million companies and 4.2 million officers we have from Illinois takes our global coverage to over 216 million companies and 297 million officers, collected from 144 national and local jurisdictions the world over.

About the dataset

Company data from Illinois is obtained from the Illinois Secretary of State, which makes the data available as bulk data files. 

The Illinois company data available in OpenCorporates will be highly up-to-date, as we will receive newly incorporated companies and updates to existing companies on at least a weekly basis. 

Both company and officer data is made available and incorporated into our database. We will be adding further officer data soon. 

Over the past few months, we have worked with the Secretary of State on the data quality so that we were happy to include it within our dataset and so it’s as useful as possible for business and society. There are still a few niggles which we are working on to allow us to include officer names and addresses, as well as branches, so these attributes will follow shortly. 

Domestic BCAs are the most common company type in Illinois according to the data we collect, followed by Limited Liability Companies, as can be seen below (figures accurate as of 15 November 2022):

Data attributes 

The Illinois Secretary of State publishes slightly different data attributes for different types of companies registered in the state, so this is reflected in our data too.


The bulk data file for corporations that we ingest from the Illinois company register offers information about three kinds of corporation: 

  • Domestic Business Corporation Act (Domestic BCA)
  • Foreign Business Corporation Act (Foreign BCA
  • Not-for-Profit

For these corporations, the following data attributes are currently available in OpenCorporates:

  • Company number
  • Company name
  • Native company number 
  • Incorporation date 
  • Current status
  • Company type
  • Officer – Agent name
  • Officer – Agent address
  • Officer – Agent type (Person or Company)
  • Filings (Annual report year)
  • Alternative names 
  • Alternative name start date
  • Alternative name end date
  • Previous names
  • Previous name start date
  • Previous name end date

Limited Liability Companies (LLCs)

The bulk data file that the Illinois Secretary of State makes available for LLCs contains the following data attributes, which we have incorporated into our data:

  • Company number
  • Native company number
  • Company name
  • Current status
  • Incorporation date
  • Dissolution date
  • Registered address
  • Officer – Agent name
  • Officer – Manager name
  • Officer – Member name
  • Officer – Start date
  • Officer – Address
  • Officer – Agent type (Person or Company)
  • Filings (Annual report year)
  • Previous name
  • Previous name start date
  • Alternative names 
  • Alternative name start date
  • Alternative name end date

Additional notes about the dataset

Company number
The data is made available by the Illinois Secretary of State as two separate bulk data files, each with their own unique company number. However when combined together, these company numbers are no longer unique. A ‘Corporation’ company can have the same company number as an ‘LLC’. 

To tackle this, we have introduced a prefix into the company numbers as ‘LLC’ and ‘CORP’ to distinguish between the two, and as per the OpenCorporates policy on company numbers, continue to provide unique identifiers per jurisdiction. 

The original ‘native company number’ can still be found within each record. 

How to access Illinois company data via OpenCorporates

  • Website
    Need to look up companies record-by-record? Simply search on our website now. All the data is there. As part of our mission, we make all our data available online.
    Search website >

  • API
    You can call on the data programmatically via our API, to power workflows, tools or automated processes.
    Find out more >

  • In Bulk
    Need the entire dataset in one go? Enquire about our Bulk Data.
    Find out more >

Existing customers

  • API subscribers: you can call on the data right now.
    View our API Reference >

  • Bulk Data subscribers: if you subscribe to our Global or North America Bulk Data subscriptions, then Illinois data will be included in your regular data delivery soon.

Public benefit cause?

As part of our mission, academics, NGOs, registered journalists, media organisations and registered nonprofits can apply for free access to our bulk data under an open public license. 

Think you qualify? Enquire here >

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