Illinois Estate Tax Forms & Deadlines
Dernière mise à jour : 10 Nov 2025 - Auteur : Alexander Foelsche CPA (US), WP (DE), RE (CH)
Illinois Estate Tax — Forms & Deadlines
One-stop page for Illinois estate tax filing: who must file, which forms you need, due dates & extensions, payment, and checklists. Illinois returns are filed with the Attorney General; tax is paid to the Trésorier de l'État de l'Illinois.
Qui doit déposer une demande ?
Formulaires de base & où les obtenir
Formulaires de l'Illinois
- Formulaire 700 — Illinois Estate & GST Tax Return (incl. IL-only QTIP schedules). Download
- Formulaire 700-EXT — Request for extension to file (and payment instructions). Download
- AG Estate Taxes hub — Forms, calculator, fact sheets. Open page
- Estate Tax Payment Form — State Treasurer remittance. Payment page
Références fédérales à joindre
- IRS Form 706 pages/schedules (or pro-forma if no federal filing), and Forms 712 (life insurance).
- Wills/trusts, appraisals, deeds, and valuation support per AG checklist.
See Form 700 instructions and the AG fact sheet for the full attachment list.
Délais, prolongations et versements
| Objet | À l'échéance | Notes |
|---|---|---|
| Illinois Form 700 | 9 mois après la date du décès | Illinois follows the federal 9-month rule; file with the AG. |
| Extension du dossier | ≈ 6 mois (typique) | AG recognizes Formulaire 4768 de l'IRS approval; or file Formulaire 700-EXT à la date d'échéance initiale. Time to pay is not extended. |
| Paiement de la taxe | By the 9-month due date | Mandat au Trésorier de l'État de l'Illinois using the Treasurer’s Estate Tax payment process. |
| Installments / deferral | Avec retour/élection | Si le gouvernement fédéral IRC § 6166 applies, Illinois generally aligns proportionally for Illinois-situs business property. |
Comment déposer et payer
Où déposer le dossier
Fichier Formulaire 700 with the Illinois Attorney General (see the form PDFs/web for addresses). Keep proof of mailing/receipt.
Comment payer
Send payment to the Trésorier de l'État de l'Illinois via the Treasurer’s Estate Tax payment page/form. Retain confirmations; refunds are issued by the Treasurer to the estate representative.
Listes de contrôle pratiques
Avant le dépôt
- Confirm residency; map Illinois-situs vs. non-Illinois assets.
- Complete federal-style schedules (706/pro-forma) and appraisals.
- Evaluate an Illinois-only QTIP election (Form 700 statement & schedules).
Lors de l'extension
- Request federal extension on Formulaire 4768 de l'IRS (attach approval) or submit Formulaire 700-EXT to the AG by the original due date.
- Remit expected tax to the Trésorier de l'État by 9 months and retain proof of payment.
FAQ
When is Illinois Form 700 due?
Neuf mois after the date of death. File with the Attorney General; payment goes to the State Treasurer.
Does Illinois accept the federal extension?
Yes. The AG recognizes Formulaire 4768 de l'IRS approvals; or request an Illinois extension via Formulaire 700-EXT. Extensions to file do pas prolonger le délai de paiement.
Where do I send payment?
Auprès de la Trésorier de l'État de l'Illinois using the Treasurer’s Estate Tax payment instructions.
What if no federal 706 is required?
You may still need to file Illinois Formulaire 700 if the Illinois threshold is exceeded; attach federal-style schedules and appraisals.