Business Organizations
Illinois law requires sole proprietorships and general partnerships to register assumed names with the County Clerk in the County where the business is conducted or transacted. Corporations, limited liability companies, limited partnerships, and limited liability partnerships must register with the Secretary of State (Please also see 805 ILCS 405 – Assumed Business Name Act). Professional service corporations with a true corporate name that does not include the name of one or more of the shareholders, or if the true corporate name continues to use the name of a deceased shareholder, the corporation must register the assumed name with the County Clerk of the county where the principal place of business is located (Please also see 805 ILCS 10 – PSC Act).
Business Registration Information in DeKalb County
Additional Contact Information
- Secretary of State’s Office – The Official Website for the Illinois Secretary of State (ilsos.gov)
- Springfield Business Information Line 217-782-6961
- Polish Business Information Line 312-793-4938
- Spanish Business Information Line 312-793-2365


