Illinois business lookup
Find an Illinois business in our directory, then confirm it with the Secretary of State, your county clerk and the right licensing agency, which in Illinois is not always IDFPR.
To look up an Illinois business, use the Illinois Secretary of State's free Business Entity Search by name or file number. Its File Detail Report shows status, registered agent, formation date and the officers or managers on file. Sole-proprietor assumed names are filed with the county clerk, and licenses are split among IDFPR, the Department of Public Health and cities such as Chicago.
Updated October 2026Search our directory first
USA Business Search lists Illinois businesses from Foursquare open place data and owner submissions, with phone numbers, websites and addresses. Begin at the Illinois hub or jump to a city:
The Chicago area is large, so add the suburb when you search a service. A plumber in Naperville and one on the North Side work under different local rules. Listings can lag behind real-world changes, and owners can claim them to correct details. We do not verify, rank or endorse the businesses listed.
Verify a business with the Illinois Secretary of State
The Business Entity Search covers corporations, LLCs and limited partnerships registered in Illinois. It is free. Search by business name (keyword, partial word or exact match) or by file number.
Open a result to see the File Detail Report, which lists:
- Entity name, file number, entity type and the state where it was formed.
- Formation or qualification date and current status (for example Active, Not Good Standing or Dissolved).
- Registered agent name and registered office address.
- President and secretary for a corporation, or managers for a manager-managed LLC.
- Any assumed names the entity has adopted with the state.
A Certificate of Good Standing for a corporation or LLC costs $25 and can be bought and printed online; not-for-profit corporations pay $5. That is the fee the Secretary of State's business services page listed as of October 2026.
Assumed names: county or state?
Illinois uses two systems, so where you search depends on who owns the business.
Sole proprietors and partnerships
They register under the Assumed Business Name Act with the county clerk. They must also publish notice once a week for three straight weeks in a local newspaper. Cook County handles this through the Cook County Clerk. Other counties set their own fees.
LLCs and corporations
They adopt an assumed name with the Secretary of State, and it shows on the File Detail Report. The fee is prorated to a five-year cycle that ends in years divisible by five. Under the LLC assumed name instructions, a filing in 2026 costs $120, as of October 2026.
Check a contractor or professional license
Illinois spreads licensing across several agencies. Knowing which one covers a trade saves time:
- IDFPR (Department of Financial and Professional Regulation) licenses roofing contractors, architects, engineers, real estate brokers and many health professions. Use the IDFPR license lookup. Roofing licenses are either limited (residential, eight units or fewer) or unlimited.
- Plumbers are licensed by the Illinois Department of Public Health, not IDFPR. Plumbing contractors register with IDPH every year.
- General contractors have no statewide license. Cities and counties handle them. Chicago's Department of Buildings issues general contractor licenses in Classes A through E, each with a project-value limit.
- Electricians are mostly licensed locally. Chicago has its own electrical contractor license.
Our plumbers in Illinois page can help you find candidates. Check each license with the agency above before you pay a deposit.
Can't find the business?
Sole proprietors and general partnerships don't register with the Secretary of State, so a search there finds nothing for them. Try the county clerk's assumed name records first. In Chicago, the city publishes its business license records on its open data portal, which helps confirm that a storefront or contractor is licensed to operate. Businesses near the state line around the Quad Cities, Metro East or Rockford may be registered in Iowa, Missouri or Wisconsin instead, so ask where the company was formed.
Starting a business in Illinois
Form an LLC
Articles of Organization cost $150, as of October 2026; confirm on the Secretary of State LLC page. Check the name in the Business Entity Search first.
Annual report
LLCs file an annual report for $75 before the first day of their anniversary month. After 60 days a $100 late penalty applies. Corporations pay $75 plus franchise tax based on paid-in capital. Figures are as of October 2026; confirm on the same page.
Most Illinois cities also require a local business license or registration, and Chicago runs its own licensing through the Department of Business Affairs and Consumer Protection.
Illinois business lookup FAQs
Is the Illinois business entity search free?
Yes. Searching and viewing the File Detail Report is free. A printed Certificate of Good Standing costs $25 for a corporation or LLC.
Who licenses plumbers in Illinois?
The Illinois Department of Public Health licenses plumbers and registers plumbing contractors. IDFPR does not handle plumbing.
Does Illinois have a state general contractor license?
No. General contractors are licensed or registered by cities and counties. In Chicago, the Department of Buildings issues the license.
Why can't I find a sole proprietor's business name?
Sole proprietors file assumed names with the county clerk, not the Secretary of State. Search the clerk's records in the county where the business operates.
What does "Not Good Standing" mean in Illinois?
It usually means the entity missed an annual report or fee. The state can later dissolve or revoke it if the problem isn't fixed.
Own an Illinois business?
Add your business to USA Business Search free, or claim your existing listing to update the phone, website and hours customers see.