State Fiduciary Income Tax

Illinois Form IL-1041: The Illinois Fiduciary Income Tax Return

Estates and trusts connected to Illinois file Form IL-1041 with IDOR — on top of, not instead of, the federal Form 1041. Here is who must file, the deadlines, the rates, and the Illinois-specific rules that differ from federal.

E-File the Federal 1041Federal Form 1041 Guide

Quick Answer

Form IL-1041 is Illinois’s fiduciary income tax return, filed with IDOR. Due: The 15th day of the 4th month after the year ends — April 15 for calendar-year filers. Tax: The 4.95% income tax, plus the 1.5% personal property replacement tax that applies to trusts (estates generally do not owe replacement tax). It is filed in addition to the federal Form 1041 — prepare the federal return first, then the state return that builds on it.

Form IL-1041 at a glance

ReturnForm IL-1041 — Illinois Fiduciary Income and Replacement Tax Return
Filed withIllinois Department of Revenue
Who must fileA resident trust or estate that files (or must file) a federal return, regardless of income; any trust or estate with net income or loss allocable to Illinois; and nonresidents with Illinois-source income not covered by pass-through withholding.
Due dateThe 15th day of the 4th month after the year ends — April 15 for calendar-year filers.
ExtensionAutomatic 6 months, no form required — October 15 for calendar-year filers. Tentative tax must still be paid by the original date.
Tax rateThe 4.95% income tax, plus the 1.5% personal property replacement tax that applies to trusts (estates generally do not owe replacement tax).
E-filingIL-1041 is supported in the IDOR MeF program through approved software.

What makes Illinois different

  • Illinois is the state where the return’s name gives the game away: “Income and Replacement Tax.” Trusts pay both the 4.95% income tax and a 1.5% replacement tax — an effective 6.45% — while estates generally pay only the 4.95%.
  • Illinois residents file based on federal filing status alone: a resident trust that files a federal 1041 files an IL-1041 even with zero Illinois income.

The federal return comes first

Form IL-1041 does not replace the federal filing — an estate or trust that meets the federal thresholds ($600 of gross income, any taxable income for a trust, or a nonresident alien beneficiary) files the federal Form 1041 with the IRS and then the Illinois return with IDOR, which generally starts from the federal figures. The practical workflow: finish the federal 1041 and its Schedule K-1s, then carry the numbers into Form IL-1041. Our federal Form 1041 guide covers the thresholds, deadlines, and elections, and the Schedule K-1 guide explains what beneficiaries do with their share.

Start with the federal Form 1041

Prepare and e-file the federal fiduciary return through the IRS MeF system with an electronic acknowledgment — the foundation the Illinois return builds on.

E-File the Federal 1041

Illinois fiduciary tax FAQs

Who must file Illinois Form IL-1041?
A resident trust or estate that files (or must file) a federal return, regardless of income; any trust or estate with net income or loss allocable to Illinois; and nonresidents with Illinois-source income not covered by pass-through withholding.
When is Form IL-1041 due?
The 15th day of the 4th month after the year ends — April 15 for calendar-year filers. Extension: Automatic 6 months, no form required — October 15 for calendar-year filers. Tentative tax must still be paid by the original date.
What is the Illinois fiduciary tax rate?
The 4.95% income tax, plus the 1.5% personal property replacement tax that applies to trusts (estates generally do not owe replacement tax). Rates and thresholds change — verify against the current Form IL-1041 instructions from Illinois Department of Revenue before computing.
Do I still file the federal Form 1041 if I file Form IL-1041?
Yes — they are separate obligations. The federal Form 1041 goes to the IRS under the federal $600 gross-income (or any-taxable-income) thresholds, and Form IL-1041 goes to IDOR under Illinois's own rules. Most fiduciaries prepare the federal return first, since the state return typically starts from federal amounts.
What is the Illinois replacement tax on a trust?
The personal property replacement tax is a 1.5% tax on trust net income, collected by the state for local governments (it replaced the abolished local personal property tax). It applies to trusts but generally not to estates — one of the few state fiduciary regimes where estates and trusts face different total rates on the same return.

Other state fiduciary guides

Ohio Form IT 1041 · New Jersey Form NJ-1041 · Georgia Form 501 · North Carolina Form D-407 · Michigan Form MI-1041 · Virginia Form 770 · all states

Disclaimer: State filing thresholds, rates, and extension rules change — verify current requirements in the Form IL-1041 instructions published by Illinois Department of Revenue before filing. This page is general information, not tax advice. TaxFilingCenter is an IRS-authorized e-file provider for federal returns and does not provide legal or tax advice.