Illinois Business Lookup: The File Detail Report, Field by Field

An Illinois business lookup returns a File Detail Report, and it is unusually generous: Illinois publishes people on the free record. A corporation's report names the president and secretary with their addresses; an LLC's names its managers. Most states publish a registered agent and stop. If you need the Illinois population rather than one entity at a time, the Illinois company directory covers registered entities with industry, size and contact breakdowns attached.

The report comes in two shapes depending on entity type, and the difference matters enough to treat them separately.

Corporation File Detail Report — every field

• Entity Name
• File Number
• Status
• Entity Type
• Type of Corp
• Incorporation Date (Domestic) or Qualification Date (Foreign)
• State
• Agent Name
• Agent Change Date
• Agent Street Address
• Agent City
• Agent Zip
• President Name & Address
• Secretary Name & Address
• Duration Date
• Annual Report Filing Date
• For Year
• Old Corp Name
• Assumed Name

LLC File Detail Report — every field

• Entity Name
• File Number
• Status — shown with "On " when the entity is dissolved
• Entity Type
• Type of LLC
• File Date, or Organization/Admission Date
• Jurisdiction
• Agent Name
• Agent Change Date
• Agent Street Address
• Agent City
• Agent Zip
• Principal Office
• Management Type
• Duration
• Annual Report Filing Date
• For Year
• Series Name
• Managers — name and address

What an Illinois entity record contains

A self-contained summary. The Illinois Secretary of State File Detail Report takes two forms. A Corporation File Detail Report carries Entity Name, File Number, Status, Entity Type, Type of Corp, Incorporation Date (Domestic) or Qualification Date (Foreign), State, Agent Name, Agent Change Date, Agent Street Address, Agent City, Agent Zip, President Name & Address, Secretary Name & Address, Duration Date, Annual Report Filing Date, For Year, Old Corp Name and Assumed Name. An LLC File Detail Report carries Entity Name, File Number, Status — shown with "On " when dissolved — Entity Type, Type of LLC, File Date or Organization/Admission Date, Jurisdiction, Agent Name, Agent Change Date, Agent Street Address, Agent City, Agent Zip, Principal Office, Management Type, Duration, Annual Report Filing Date, For Year, Series Name, and Managers with name and address. Illinois is notable for publishing named individuals on the free record: president and secretary for a corporation, managers for an LLC, each with an address.

Reading the report

Status carries a date on an LLC. The LLC report shows status with "On " when the entity is dissolved, so you get the when alongside the what. Read both; a dissolution three weeks ago and one from 2011 are different facts about a company.

Old Corp Name and Assumed Name are identity-resolution gold. A corporation that has renamed keeps its former name on the record, and assumed names sit alongside it. If you are deduplicating a CRM, these two fields resolve the "is this the same company?" question that a name match alone cannot.

Agent Change Date is a signal, not just metadata. A registered agent that changed recently often accompanies a change in counsel, ownership or state of operation. It is one of the few movement indicators the free record gives you.

Series Name matters for Illinois specifically. Illinois recognises series LLCs, and the series name appears on the report. Treating a series as a separate company, or collapsing it into its parent, are both wrong in different ways depending on what you are counting.

Duration and Duration Date. Entities are not always perpetual. Check it before assuming an active status will persist.

How to search, step by step

1. Search by File Number where you have one — it resolves to a single entity.
2. Otherwise search the entity name, then confirm using File Number, Old Corp Name or Assumed Name rather than trusting a name match.
3. Pick the right report shape. Corporation and LLC reports carry different fields; do not expect President and Secretary on an LLC, or Managers on a corporation.
4. Read Annual Report Filing Date and For Year together — they tell you how current the rest of the record is.
5. Record the File Number as your match key.

Where the Illinois record stops

Generous as the field list is, it is a legal-identity record. There is no industry classification, no employee count, no revenue, no website and no company phone number. The people it names are officers of record, not commercial contacts, and the addresses are filing addresses.

It is also a per-entity lookup. Illinois does not offer a public bulk route through this tool, so a question shaped like "every Illinois LLC in a sector above a size" cannot be answered here. Do not attempt to automate searching against a state registry to get around that — several states prohibit automated querying outright and treat it as grounds for suspending access. The honest position is that the registry is built for one entity at a time, and a question about a segment needs a different source.

That is the gap a firmographic directory fills: the same registered entities, classified and sized, queryable as a set. The United States company directory covers the national file and breaks down by state.

Source Register

On the sourcing. These are archived renderings of the official Illinois Secretary of State tool, preserved in federal court filings and a federal agency archive, rather than the live page. The 2020 rendering shows a restructured, sectioned layout while the field names hold across all four documents, which is why this guide describes fields and not screen positions: the labels have proven stable across at least five years, the arrangement has not.

Not claimed: that President, Secretary or Managers are search fields. They appear on the returned report. Whether you can search by them is unverified, and this guide does not say that you can.