Illinois field guides / 16 decision paths
Illinois guides
Choose the decision in front of you: an entity, a filing, a tax date or your next compliance step.
Illinois statutory references supplied for the October 28, 2026 review; confirm current official instructions.
Start with your first-year costsFormation decisions
Illinois LLC Articles of Organization — Form LLC-5.5
Illinois LLC Articles of Organization — Form LLC-5.5
Illinois Series LLC — Forms LLC-5.5(S) & LLC-37.40
Illinois Series LLC — Forms LLC-5.5(S) & LLC-37.40
Illinois PLLC / Professional Service Corporation & IDFPR
Illinois PLLC / Professional Service Corporation & IDFPR
Illinois LLC & C-Corp for Non-US Founders — ITIN & Form 5472
Illinois LLC & C-Corp for Non-US Founders — ITIN & Form 5472
Costs
Start this decision pathTax & timing
Illinois 1.5% Personal Property Replacement Tax
Illinois 1.5% Personal Property Replacement Tax
Illinois $1,000,000 Franchise Tax Exemption
Illinois $1,000,000 Franchise Tax Exemption
Illinois S-Corp Election — Form 2553 & IL-1120-ST
Illinois S-Corp Election — Form 2553 & IL-1120-ST
Filing paths
Illinois Assumed Names vs. County Clerk Publication
Illinois Assumed Names vs. County Clerk Publication
Chicago BACP Limited Business License & Cook County LLC
Chicago BACP Limited Business License & Cook County LLC
MyTax Illinois REG-1 — Sales & Withholding Registration
MyTax Illinois REG-1 — Sales & Withholding Registration
Illinois Foreign Qualification — LLC-45.5 & BCA 13.15
Illinois Foreign Qualification — LLC-45.5 & BCA 13.15
Illinois Name Availability & LLC-1.15 Reservation
Illinois Name Availability & LLC-1.15 Reservation
Compliance
Illinois Annual Report — Anniversary-Month Deadlines
Illinois Annual Report — Anniversary-Month Deadlines
Illinois Registered Agent — 805 ILCS 180/1-35
Illinois Registered Agent — 805 ILCS 180/1-35
Illinois Administrative Dissolution & LLC-35.40 Reinstatement
Illinois Administrative Dissolution & LLC-35.40 Reinstatement
Corp USA is not a law firm and does not provide legal advice. State fees are pass-through; service fees and taxes are separate.
About Corp USA Illinois