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. 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). 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. All tax obligations must be satisfied before making final distributions.

Yes. Illinois imposes a state estate tax on estates exceeding $$4,000,000. 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 executor checklist covers all filing responsibilities in order.

Tax Filing After Death in Illinois

After a death in Illinois, both federal and state tax returns must be filed. A final income tax return covers the deceased's income through the date of death, and a separate fiduciary return may be needed if the estate earns income during administration.

Estates in Illinois above the $4,000,000 exemption must file a state estate tax return. Calculate the potential tax with the death tax calculator.

Filing deadlines depend on the type of return. Final income tax returns are generally due April 15 of the year following death. Estate tax returns, where applicable, are typically due nine months after the date of death. The Illinois executor checklist tracks all deadlines in order.

SimplyTrust Editorial·Updated May 31, 2026

Legal Sources

35 ILCS 405/2

Data sourced from Illinois statutes and official state code. How we research.

Illinois Estate Planning Resources

In-depth guides covering Illinois probate laws, trust requirements, and estate planning strategies.

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.

State

Approximate Estate Value

Estate earns income

Interest, dividends, rent, or other income received after date of death

Illinois Tax Filing Checklist

2 filings required

0 of 2 completed0%

Federal

File final income tax return

A final federal income tax return is required for income earned from January 1 through the date of death.

Form: IRS Form 1040

Deadline: April 15 following year of death

Write "DECEASED" across the top. If filing jointly with surviving spouse, include both incomes. Attach Form 1310 if claiming a refund.

Download Form File Online

File estate income tax returnNot required

IRS Form 1041 is only required if the estate earns $600 in gross income or more during administration.

File estate tax returnNot required

The estate value ($0) is below the federal exemption of $15,000,000. IRS Form 706 is generally not required.

Illinois

File final income tax return

A final state return is required for income earned through the date of death.

Form: IL-1040

Deadline: April 15 following year of death (automatic 6-month extension to October 15)

Write "deceased" and date of death above taxpayer name. Attach Form IL-1310 if non-spouse claims refund. 35 ILCS 5/502.

Download Form File Online

File estate income tax returnNot required

A fiduciary return is only required if the estate earns income above the filing threshold (Required if estate has IL-source net income/loss, is an IL resident filing federal Form 1041, or is a nonresident with IL-source income — 35 ILCS 5/502).

File estate tax returnNot required

The estate value ($0) is below Illinois's exemption of $4,000,000.

Tax Clearance Not Required

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.

This tool provides general information about tax filing requirements after death. Tax situations vary based on individual circumstances. Consult a licensed tax professional or CPA for advice specific to your situation.

Frequently Asked Questions

Tax Filing After Death in Illinois

Estates in Illinois above the $4,000,000 exemption must file a state estate tax return. Calculate the potential tax with the death tax calculator.

SimplyTrust Editorial·Updated May 31, 2026

Legal Sources

35 ILCS 405/2

Data sourced from Illinois statutes and official state code. How we research.

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