Does Illinois have inheritance or gift tax?

Illinois imposes an estate tax, not an inheritance tax. There is no separate Illinois gift tax; however, certain lifetime taxable gifts are included in the Illinois estate computation.

What’s the 2025 Illinois estate tax threshold and rate structure?

The exclusion is $4,000,000 (not indexed and not portable). Illinois uses the pre-2005 federal state death tax credit schedule (0.8% up to 16%) with an interrelated computation.

How are nonresidents taxed on Illinois property?

Nonresidents are taxed on Illinois-situs real and tangible personal property. The estate computes the full Illinois tax and then prorates by Illinois-situs assets divided by total assets.

When is the Illinois estate tax return due and how do I file?

The Illinois return (Form 700) is generally due within 9 months of death. Extensions are available (Form 700-EXT or federal Form 4768), but interest may accrue until payment.

Is there an Illinois-only QTIP election?

Yes. Illinois allows a QTIP election for state purposes even if a different federal QTIP is chosen. The election is made on Form 700.

Illinois Estate Tax Guide

Q: Does Illinois have an estate or an inheritance tax?

Illinois has a state estate tax paid by the estate, based on federal concepts with Illinois-specific filing rules and a separate state exclusion.

Q: When is Illinois Form 700 due?

Nine months after death. You can extend time to file by about six months (federal Form 4768 or Illinois Form 700-EXT). Payment remains due at nine months.

Q: How are nonresidents taxed?

Only on Illinois-situs real and tangible property. Most nonresident intangibles are excluded unless an Illinois business situs exists.

Q: Which forms do I use?

Form 700 (estate return) and, if needed, Form 700-EXT (extension). File with the Attorney General; send payment to the State Treasurer.

Illinois Estate Tax & Probate Guide

Last updated: 18 Oct 2025 • Author: Alexander Foelsche CPA (US), WP (DE), RE (CH)

Illinois Estate Tax & Probate — Complete Guide

What executors and families need to know about Illinois probate and estate tax: who files, what’s taxable, nonresident rules, forms, deadlines & extensions, elections (Illinois-only QTIP, charitable), valuation, and planning—plus a calculator, case notes, and a nonresident guide.

📘

Quick orientation: Illinois imposes a state estate tax under 35 ILCS 405. The Illinois return is Form 700 and is generally due 9 months after death. Federal extensions (Form 4768) are recognized, or you can request an Illinois extension (Form 700-EXT), but payment is still due at 9 months and is remitted to the Illinois State Treasurer.

Illinois Probate Basics

Courts & intestacy

Probate is handled in the Illinois circuit courts. If there is no will, distribution follows Illinois intestacy statutes. Ancillary probate is common where nonresidents own Illinois real property.

Typical probate steps

Open estate → appoint personal representative → notices → inventory & appraisals → pay debts/expenses/taxes → accountings → distribution & close.

Illinois Estate Tax — At a Glance

Who must file?

Personal representative files Form 700 when an Illinois estate tax is due or a filing is needed to make elections; nonresidents file for Illinois-situs assets only.

Tax base

Computation is tied to the pre-2005 federal state death tax credit framework with Illinois-specific mechanics; Illinois maintains its own exclusion (commonly referenced as $4,000,000 for recent years).

IL-only QTIP

Illinois allows a separate state QTIP election on a timely filed Form 700, even if no federal QTIP is made. Inclusion occurs at the survivor’s death.

Nonresidents

Illinois taxes Illinois-situs real property and tangible personal property; most intangibles of nonresidents are outside the Illinois base unless a business situs exists in Illinois.

Due date & extension

Return and payment due in 9 months. You can extend time to file (federal Form 4768 or Illinois Form 700-EXT); time to pay is not extended.

Official Pages, Forms & Where to File/Pay

Illinois Attorney General — Estate Taxes (Form 700, 700-EXT, fact sheets, calculator).
Statute: Illinois Estate & GST Tax Act (35 ILCS 405).
Payment: Illinois State Treasurer — Estate Tax payments (payment form & instructions).
Federal: IRS Form 706 & instructions — IRS page.

Illinois Situs vs. Non-Situs (for Nonresidents)

Asset type	Illinois treatment	Notes
Real property in Illinois	Included	Use local appraisals; common for ancillary probate.
Tangible personal property kept in IL	Included	Boats, vehicles, equipment, art physically in IL.
Intangibles (stock, bank/brokerage)	Generally excluded	Excluded for nonresidents unless a business situs exists in Illinois.
Entity interests (LLC/partnership)	Generally excluded	Treated as intangibles; avoid IL business-situs facts.

If you’re a nonresident with Illinois assets, see the Nonresident Guide for examples and a filing checklist.

Filing Mechanics, Deadlines & Payment

When to file: Form 700 due within 9 months from date of death (same as federal).
Extension to file: typically 6 months (attach IRS 4768 approval or file Illinois Form 700-EXT). Payments remain due at 9 months.
Where to file: File the return with the Illinois Attorney General.
Where to pay: Remit tax to the Illinois State Treasurer using the Treasurer’s estate tax payment form/instructions.
Installments: If federal IRC §6166 applies, Illinois generally aligns proportionally for Illinois-situs business interests.

Planning Ideas to Reduce Illinois Estate Tax

IL-only QTIP. Make a state QTIP election to defer tax at the first death even if no federal QTIP is desired.
Credit shelter & charitable planning. Coordinate with the interrelated Illinois computation; attach robust support.
Nonresident situs. Limit Illinois-situs assets for nonresidents; avoid business situs for intangibles.
Valuation & deductions. Use strong local appraisals; keep court orders/invoices to support deductions.
Liquidity & §6166. Stage cash for the 9-month payment; align any federal §6166 election with Illinois schedules.

Tools & Subpages

Calculator

Estimate Illinois estate tax for residents and nonresidents; model IL-only QTIP and deductions.

Open Calculator

Forms & Deadlines

All forms (Form 700 / 700-EXT) with due dates, extensions, payments, and checklists.

Open Forms & Deadlines

Nonresident Guide

Who must file, what is Illinois-situs, reduction mechanics, examples, and checklists.

Open Nonresident Guide

Case Notes

Authorities-first summaries on conformity, IL-only QTIP, situs, valuation, and timing.

Open Cases

Planning

Strategies to reduce exposure, allocate burden, and fund payments—checklists and drafts.

Open Planning

FAQs

Does Illinois have an estate or an inheritance tax?

Illinois has a state estate tax (paid by the estate). It follows federal concepts with Illinois-specific filing rules and a separate state exclusion.

When is Illinois Form 700 due?

Nine months after the date of death. You can extend time to file by about six months (federal Form 4768 approval or Illinois Form 700-EXT); time to pay is not extended.

How are nonresidents taxed?

Only on Illinois-situs real and tangible property. Most nonresident intangibles are excluded unless an Illinois business situs exists.

Which forms do I use?

Form 700 (estate return) and, if needed, Form 700-EXT (extension). File with the Attorney General; send payment to the State Treasurer.

Need help filing or planning?

We assist with Illinois probate coordination, resident and nonresident filings, IL-only QTIP and charitable elections, valuation documentation, and §6166 liquidity planning.

Talk to an advisor → taxrep.us/contact