How Do I File Taxes for a Deceased Person in Illinois?
Find out which tax returns you need to file after someone dies. See state-specific forms, deadlines, and whether tax clearance is required.
Frequently Asked Questions
At minimum, a final federal income tax return (Form 1040) and a final Illinois income tax return (IL-1040) must be filed for income earned through the date of death.35 ILCS 5/502; 35 ILCS 405/1 et seq.Verified Jul 13, 2026 If the estate earns income during administration, a federal fiduciary return (Form 1041) and Illinois fiduciary return (IL-1041) may also be required. Estates exceeding $$4,000,000 must also file a Illinois estate tax return.
The final federal and Illinois income tax returns are due april 15 following year of death (automatic 6-month extension to october 15).35 ILCS 5/502; 35 ILCS 405/1 et seq.Verified Jul 13, 2026 The fiduciary return is due april 15 (calendar year); automatic 6-month extension.
No. Certificate of Discharge from estate tax lien available via Form 700 checkbox (handled by Attorney General). IDOR Form ITR-1 available for business tax clearance but not required for probate.35 ILCS 5/502; 35 ILCS 405/1 et seq.Verified Jul 13, 2026 All tax obligations must be satisfied before making final distributions.
Yes. Illinois imposes a state estate tax on estates exceeding $$4,000,000.35 ILCS 405/2Verified Jul 13, 2026 This is separate from the federal estate tax. Estates above the state threshold must file a state estate tax return even if no federal estate tax is owed. See the full breakdown with the Illinois death tax calculator.
Yes. Estate size does not affect the requirement to file a final income tax return. A final Form 1040 is required regardless of estate value if the deceased had income. What smaller estates typically avoid is the federal estate tax return (Form 706) and the Illinois estate tax return (for estates over $$4,000,000).
The executor named in the will (or the court-appointed administrator) is responsible for filing the final income tax return and any estate tax returns. If the deceased was married, the surviving spouse can file a joint federal return for the year of death. For trust assets, the successor trustee handles fiduciary tax returns. The Illinois estate settlement plan covers all filing responsibilities in order.
Illinois Estate Planning Resources
In-depth guides covering Illinois probate laws, trust requirements, and estate planning strategies.




