Illinois

This guide is outdated and will be removed on 1 November 2026. The up-to-date Illinois reference is on the Illinois country page.

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This guide contains public integration notes for Illinois. Use it for identifier formats, search behavior, and state-specific caveats. The live source of truth for coverage, pricing, data sources, documents, legal forms, roles, and status values is the pricing page.

Illinois coverage, pricing, and sources

Open the current catalog for supported datapoints, documents, sources, identifiers, and availability.

This jurisdiction may be in preview or limited availability. Check the live pricing page or contact support before relying on it in production.

State details below are preserved as integration notes. If a table or example conflicts with the live pricing page, use the pricing page as the source of truth and contact support.

Data Sources
Company Identifiers
Search Capabilities
Quirks & Gotchas
Mappings
- Legal Forms
- Entity Statuses
Data Availability

Data Sources

Illinois uses a single integration against the Illinois Secretary of State, Department of Business Services. The register covers approximately 3.5 million entities filed under the Illinois Business Corporation Act, the General Not-for-Profit Corporation Act, the Limited Liability Company Act, and related statutes, including domestic and foreign corporations, LLCs, professional service entities, benefit corporations, agricultural cooperatives, and not-for-profit corporations. The Illinois Business Data Transparency Act (Public Act 102-0049, effective 2022-01-01) requires the Secretary of State to publish daily bulk distributions of the business entity database. These bulk files are the sanctioned machine-readable path; Topograph uses them as the primary data source.

ILSOS daily bulk distribution. Published daily by the Secretary of State at ilsos.gov. Covers corporation and LLC master records, names, manager/member rosters, and registered agents. The snapshot refreshes daily; individual records may lag up to 24 hours from a filing event.

Same data in both modes. Prefill (mode: "prefill") and verification (mode: "verification") requests are both served from the daily bulk distribution and return the same data.

Company Identifiers

Query Identifiers

Identifier Type	Format	Example	Notes
ILSOS File Number	8 digits, leading zeros included	`08142220`	Assigned by the Illinois Secretary of State. Illinois runs independent File Number sequences for corporations and LLCs. The same 8-digit number can refer to two different entities (one corporation, one LLC). To target a specific entity, supply the Topograph compound ID.
Topograph compound ID	`C` or `L` prefix + 8 digits	`C08142220`	The prefix is ours, not the register’s: `C` for an entity on the corporation register (including not-for-profit corporations), `L` for a limited liability company. This is the `id` of every search result and the `company.id` of every profile. Use it whenever you need to target a specific entity and avoid ambiguity.

Search by bare 8-digit File Number returns all matching entities across both the corporation and LLC sequences. Use the compound ID (C08142220 or L08142220) to resolve to a single entity. /v2/company refuses a bare number that matches both a corporation and an LLC. The identifiers.entityType field in the response confirms which family was matched.

Identifiers in API Response

Identifier	Format	Example	Found In
`fileNumber`	8 digits, leading zeros included, no prefix (`company.id` carries the `C` / `L` prefix)	`08142220`	All entities

Legal Entity Identifier (LEI)

GLEIF is the supplementary data source for this identifier. company.identifiers.lei is returned when fileNumber has a unique match against Illinois registration or validation references in GLEIF and the legal name agrees. Corporations and LLCs use separate number sequences, so a number match alone is insufficient. An LEI (Legal Entity Identifier) has 20 uppercase letters and digits, ending in two check digits. Coverage varies by entity. The field is omitted when no unambiguous match is available. Lapsed or retired LEIs may be returned; annulled records are excluded.

Search Capabilities

Search Type	Pattern	Example	Match Type	Expected Results
By Name	2-200 chars	`"Walgreen"`	Relevance-ranked match on the legal name	Multiple results
By File Number (bare)	8 digits	`08142220`	Exact	Up to 2 results (one corp + one LLC if both exist)
By Compound ID	`C` or `L` + 8 digits	`C08142220`	Exact	Single entity

Active companies only

Search can return companies that are no longer active. Each result carries the register’s status, so activeOnly=true removes the inactive ones.

Quirks & Gotchas

Quirk	Details
File Number sequences overlap across entity families	Illinois maintains independent File Number sequences for corporations and LLCs. Two different entities can share the same 8-digit number. Always use the Topograph compound ID (`C` or `L` prefix) when you need to unambiguously identify a single entity.
Annual report freshness	Corporations and LLCs file one annual report per year. Officer and address data in the snapshot may be up to 12 months old, reflecting the most recent annual filing. This is a structural property of the Illinois filing cadence, not a Topograph limitation.
LLCs disclose managers and members	Unlike many US states, Illinois LLCs disclose their managers and (where applicable) members in the public bulk distribution. These positions appear in `otherKeyPersons` with their filed titles and member-management context. A bulk position does not establish company-specific signing powers.
Limited Partnerships and LLPs are out of scope for v1	LPs and LLPs are available through the live portal but are not included in the daily bulk distribution. They are excluded from v1 coverage.
No ownership percentages	Illinois does not collect or publish ownership percentages for any entity type. Returned people include names and filed roles but no equity stakes.
No activity codes	The Secretary of State does not collect NAICS, NACE, or ISIC codes. A coarse 56-entry purpose code is available for corporations only and is not currently surfaced.
Series LLCs	Illinois is one of the few states that allows Series LLCs. The parent LLC is identified by its legal form (`Series Limited Liability Company`). Individual series are not returned as separate entities.
State-level DBAs	Assumed names (DBAs) registered at the state level are included in the bulk distribution and indexed for search. County-level DBA registrations are not included.
Nonprofits are in scope	Not-for-profit corporations filed under the Illinois General Not-for-Profit Corporation Act are included in the corporation bulk distribution and covered by this integration. Fundraising registration through the Illinois Charitable Trust Bureau is out of scope.

Mappings

Legal Forms

Legal form is derived from the entity type code in the ILSOS bulk distribution, sourced from the published Corp and LLC data dictionaries. The full legal form table is available on the pricing page.

Illinois entity types (summary)

Local Name	Standardized	Category
Domestic Corporation	Corporation	Business Corporation Act
Foreign Corporation	Corporation	Business Corporation Act
Not-For-Profit Corporation	Nonprofit Organization	Not-for-Profit Corporation Act
Agricultural Cooperative	Cooperative	Ag-cooperative (unique to IL)
Domestic Limited Liability Company	Limited Liability Company	LLC Act
Foreign Limited Liability Company	Limited Liability Company	LLC Act
Low-Profit Limited Liability Company (L3C)	Limited Liability Company	LLC Act
Series Limited Liability Company	Limited Liability Company	LLC Act (unique to IL)

The full legal form table with source codes and ISO 20275 mappings (where available) is on the Illinois pricing page.

Entity Statuses

Status values come from the register’s own status codes in the ILSOS bulk data dictionaries (Corp CORP-STATUS field and LLC LL-STATUS field). A dissolved corporation is returned as Voluntary Dissolution or Involuntary Dissolution when the register records which kind of dissolution it was, and as Dissolved otherwise.

Status	Applies To
Goodstanding	Corps and LLCs
Not Good Standing	LLCs
Reinstated	Corps and LLCs
Domesticated	LLCs
Redomisticated	Corps
Intent to Dissolve	Corps
Unacceptable Payment	Corps
Registered Name Expiration	Corps
Registered Name Cancellation	Corps
Special Act Corporation	Corps
Ag-Coop	Corps
Agent Vacated	Corps and LLCs
Hold	LLCs
Bankruptcy	Corps and LLCs
Voluntary Dissolution	Corps and LLCs
Involuntary Dissolution	Corps and LLCs
Administratively Dissolved	Corps and LLCs
Dissolved	Corps
Withdrawn	Corps and LLCs
Revoked	Corps and LLCs
Expired	Corps
Void	LLCs
Merged/Consolidated	Corps
Merged	LLCs
Converted	Corps and LLCs

Data Availability

Data Point	Available	Notes
Company name	Yes	Current legal name
Company status	Yes	From the register’s status codes, for corporations and LLCs, in both modes
Registration date	Yes	ILSOS initial filing date
Legal address	Partial	LLCs only (records office address). Corporations publish no company address, so none is returned.
Legal form	Yes	Closed enum mapped to standardized categories
Legal representatives	Yes	Corps: president. LLCs: managers, and members holding manager authority. LP/LLP: out of scope for v1.
Other key persons	Yes	Corps: secretary and registered agent. LLCs: registered agent.
Registered agent	Yes	Returned under `otherKeyPersons` in both modes
Assumed names (DBAs)	Yes	State-level assumed names from the bulk distribution
Series LLC sub-series	No	Series LLC parents are identified by their legal form; individual series are not returned
Activity codes	No	Not collected by the Illinois Secretary of State
Shareholders	No	Not filed with the Secretary of State for any entity type
UBOs	No	No public beneficial ownership register at the state level
Trade Register Extract	No	No documents are currently offered for Illinois
Certificates of Good Standing	Roadmap	Paid document issued by the Secretary of State. Not currently offered through Topograph.
Certified copies	No	Paid documents mailed by the Secretary of State; not available through the public portal
Financial data	No	Not collected
County-level DBAs	No	County-level DBA filings are not part of the Secretary of State database

Example API Responses

Search by Name

curl -X GET "https://api.topograph.co/v2/search?country=US-IL&query=Acme" \
  -H "x-api-key: YOUR_API_KEY"

[
  {
    "id": "C09000001",
    "legalName": "ACME MANUFACTURING, INC.",
    "countryCode": "US-IL",
    "matchReason": {
      "matchType": "default"
    },
    "address": {
      "region": "IL",
      "countryCode": "US"
    }
  }
]

Search by Compound ID

curl -X GET "https://api.topograph.co/v2/search?country=US-IL&query=C09000001" \
  -H "x-api-key: YOUR_API_KEY"

[
  {
    "id": "C09000001",
    "legalName": "ACME MANUFACTURING, INC.",
    "countryCode": "US-IL",
    "matchReason": {
      "matchType": "id"
    }
  }
]

Company Profile

curl -X POST "https://api.topograph.co/v2/company" \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"countryCode": "US-IL", "id": "C09000001", "dataPoints": ["company", "legalRepresentatives", "otherKeyPersons"], "mode": "prefill"}'

{
  "company": {
    "id": "C09000001",
    "countryCode": "US-IL",
    "identifiers": { "fileNumber": "09000001" },
    "legalName": "ACME MANUFACTURING, INC.",
    "registrationDate": "2005-03-15",
    "legalForm": {
      "localName": "Domestic Corporation",
      "standardized": "Corporation"
    },
    "status": {
      "localName": "Goodstanding",
      "active": true
    }
  },
  "legalRepresentatives": [
    {
      "entityId": "person_001",
      "type": "individual",
      "role": { "localName": "President", "standardized": "President" },
      "individual": {
        "name": { "fullName": "Jane A. Smith" }
      }
    }
  ],
  "otherKeyPersons": [
    {
      "entityId": "person_002",
      "type": "individual",
      "role": { "localName": "Secretary", "standardized": "Secretary" },
      "individual": {
        "name": { "fullName": "Robert B. Johnson" }
      }
    }
  ]
}

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Illinois coverage, pricing, and sources

Table of Contents

Data Sources

Company Identifiers

Query Identifiers

Identifiers in API Response

Legal Entity Identifier (LEI)

Search Capabilities

Active companies only

Quirks & Gotchas

Mappings

Legal Forms

Entity Statuses

Data Availability

Example API Responses

Search by Name

Search by Compound ID

Company Profile

​Start here

Illinois coverage, pricing, and sources

​Table of Contents

​Data Sources

​Company Identifiers

​Query Identifiers

​Identifiers in API Response

​Legal Entity Identifier (LEI)

​Search Capabilities

​Active companies only

​Quirks & Gotchas

​Mappings

​Legal Forms

​Entity Statuses

​Data Availability

​Example API Responses

​Search by Name

​Search by Compound ID

​Company Profile

Start here

Table of Contents

Data Sources

Company Identifiers

Query Identifiers

Identifiers in API Response

Legal Entity Identifier (LEI)

Search Capabilities

Active companies only

Quirks & Gotchas

Mappings

Legal Forms

Entity Statuses

Data Availability

Example API Responses

Search by Name

Search by Compound ID

Company Profile