# Illinois

Company data from the Illinois business register, through the Topograph API.

> **Beta**: this country is in early development. Some datapoints or documents may be missing, the integration may be unstable, prices may change without notice, and it is not covered by SLAs.

## Overview

Topograph reads Illinois Secretary of State, Department of Business Services and returns the company profile, legal representatives and other key persons of Illinois companies through one API.

## Coverage

What comes back for each datapoint and document, as on the coverage matrix.

Requests run in prefill mode (fast) or verification mode (the authoritative register answer).

| Datapoint | Returned |
| --- | --- |
| Company profile | Yes |
| Legal representatives | Yes |
| Other key persons | Yes |

| Document | Returned |
| --- | --- |
| Register extract | No |
| Articles of association | No |
| Financials | No |
| UBO extract | No |

### Speed

A company profile typically comes back from the register in 1 s in prefill mode and 1 s in verification mode. These are typical observations, not a service-level commitment: set your timeouts well above them.

## Sources

The registers this country’s data comes from. Secondary sources only enrich or check what the registers return.

- **[Illinois Secretary of State, Department of Business Services](https://www.ilsos.gov/data/bus-serv-home.html)**: Official Illinois state business entity register maintained by the Secretary of State, Department of Business Services. Covers ~3.5M entities (corporations, LLCs, not-for-profits, agricultural cooperatives). Responses are served from a daily full-snapshot of the statutory bulk distribution (Business Data Transparency Act, Public Act 102-0049, effective 2022-01-01): corporation and LLC master records, names, and managers/members. This distribution is published by the Secretary of State itself and carries the register's own status codes, so it is the authoritative source rather than a third-party copy; the Department mandates that it be published openly and daily, and prohibits automated querying of the public inquiry portal.
- **[GLEIF (Legal Entity Identifiers)](https://www.gleif.org/en/lei-data/gleif-golden-copy/download-the-golden-copy)** (secondary): Global Legal Entity Identifier Foundation – Legal Entity Identifier reference data

## Identifiers

Request a company by its ILSOS File Number as the `id`, with `countryCode` set to `US-IL`. Its format, validation rules and an example value are in the full reference.

## The full Illinois reference

The full reference covers how each datapoint is sourced and mapped, the vocabularies the API returns, the documents you can order and exact example responses. It is free with a Topograph account.

| In the full reference | Entries |
| --- | --- |
| Identifiers and formats | 2 |
| Search patterns | 3 |
| Quirks | 9 |
| Legal forms | 11 |
| Officer roles | 7 |
| Company statuses | 25 |
| Example responses | 3 |

- Create a free account: https://www.topograph.co/sign-up?redirect_url=%2Fcountries%2Fus-il
- Sign in: https://www.topograph.co/sign-in?redirect_url=%2Fcountries%2Fus-il

With a session, https://www.topograph.co/countries/us-il.md returns the full reference as Markdown. Assistants signed in to the [Topograph Wizard MCP](https://docs.topograph.co/guides/topograph-mcp) can read it there too.

## Illinois business register guide

[Illinois business register guide](https://www.topograph.co/guides/business-registers-in-illinois-united-states): how the register works, what it publishes and which documents it issues.

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Source: https://www.topograph.co/countries/us-il