Illinois Estate Tax for Non-Residents: What Out-of-State Heirs Must Know

Illinois does not only tax estates of people who lived and died in Illinois. If a non-resident died owning real estate or tangible personal property physically located in Illinois — a vacation home, a rental property, farmland, a boat kept at a Chicago marina — Illinois claims the right to tax a proportionate share of that estate. For executors managing cross-state estates, this is frequently a surprise.

Here is how the Illinois non-resident estate tax works, when it applies, and what the filing looks like.

Illinois Jurisdiction Over Non-Resident Property

Illinois imposes its estate tax based on where property is physically located (situs), not solely where the decedent lived. The governing principle:

• Real property physically located in Illinois is always subject to Illinois estate tax in the decedent's estate, regardless of the decedent's domicile
• Tangible personal property with a permanent situs in Illinois (registered vehicles, boats, equipment, business inventory) is also subject to Illinois taxation
• Intangible personal property (bank accounts, brokerage accounts, stock certificates, IRAs) is generally not subject to Illinois tax for non-residents — those assets follow the domicile state's rules

This means a Florida resident who dies owning a Chicago rental property and a Florida stock portfolio will face Illinois estate tax on the property's value, but not on the investment accounts.

When the Non-Resident Threshold Is Reached

The Illinois estate tax exemption is $4,000,000, but for non-residents the calculation is proportional — not a simple comparison of Illinois property value to the $4 million threshold.

The way it works: Illinois computes the tax as if the entire worldwide estate were subject to Illinois tax, then multiplies the result by the ratio of Illinois-situs property to total estate value. This is the allocation formula embedded in Form 700.

Example: A Texas domiciliary dies with a total estate of $8,000,000. Of that, $1,500,000 is a Lake County vacation home, and the remaining $6,500,000 is Texas real estate, bank accounts, and investment portfolios.

• The "Illinois proportion" is $1,500,000 / $8,000,000 = 18.75%
• Illinois computes what the full estate tax would be on $8,000,000 (roughly $625,000 after the interrelated calculation)
• Then applies the 18.75% ratio: Illinois estate tax owed ≈ $117,000

The executor is responsible for this Illinois liability even though the decedent never lived in Illinois. Illinois is entitled to its proportionate share whenever its situs property is involved.

This proportional approach means that a large out-of-state estate with modest Illinois property can still produce a meaningful Illinois tax bill. It also means that a non-resident estate with very low total value may produce minimal or zero Illinois tax even if there is some Illinois property involved.

Filing Form 700 as a Non-Resident Estate

Non-resident estates that cross the effective threshold must file Form 700 — the Illinois Estate and Generation-Skipping Transfer Tax Return — with the Illinois Attorney General's office. The geographic split applies to non-residents based on where the Illinois property is located:

• Property in Cook, DuPage, Lake, or McHenry counties → Chicago AG office
• Property in all other counties → Springfield AG office

The nine-month deadline from the date of death applies identically to non-resident estates. Extensions via Form 700-EXT are available on the same terms as resident estates.

What non-resident executors must attach to Form 700:

• A copy of the federal Form 706 (if filed) and all schedules — including the schedules covering all worldwide assets
• Appraisals for the Illinois real property (licensed Illinois appraiser preferred)
• Evidence of the situs of all tangible property in Illinois
• Documentation establishing that intangible assets are domicile-state property (account statements showing out-of-state institutions, for example)
• A copy of the death certificate

The AG's office will scrutinize the allocation calculation. If you understate the total worldwide estate to reduce the Illinois proportion, you create audit risk. If you include intangible assets in the Illinois situs column erroneously, you overstate the tax. Both errors carry penalties.

The Illinois Final Tax & Estate Tax Guide covers the Form 700 allocation calculation, supporting documentation requirements, and the certificate of discharge process for out-of-state executors managing Illinois real property.

The Certificate of Discharge Still Applies

The automatic Illinois estate tax lien attaches to Illinois real property at the moment of death — for non-residents just as for residents. Title companies in Illinois will not insure a sale of the decedent's Lake County vacation home or Chicago rental unit without the Certificate of Discharge issued by the AG's office following Form 700 review.

Even if the proportional calculation produces zero tax (because the Illinois property represents a small fraction of a large estate that keeps the effective Illinois tax near zero), you still need to document that determination and obtain the certificate. Without it, the property is effectively unsaleable.

After the AG issues the Certificate of Discharge, the executor must record it with the county Recorder of Deeds in every Illinois county where the decedent held real property. Recording fees run approximately $45 to $65 depending on formatting compliance.

Illinois Fiduciary Income Tax for Non-Resident Estates

Separate from the estate transfer tax, if the estate generates Illinois-sourced income during the probate period — rental income from the Illinois property, for example — the estate may also owe Illinois fiduciary income tax (Form IL-1041). Non-resident estates with Illinois-sourced income must complete Schedule NR to properly allocate that income to Illinois.

This is filed with the Illinois Department of Revenue, not the Attorney General. The two filings — Form 700 with the AG, and Form IL-1041 with IDOR — are separate obligations that may both apply to the same non-resident estate.

For a clear breakdown of how these forms interact and which agency handles each, see the Illinois Form 700 Instructions post.

Practical Steps for Out-of-State Executors

If you are administering an estate from outside Illinois, several practical realities differ from managing a resident estate:

Retaining an Illinois appraiser. Remote executors often try to use the decedent's home-state appraiser for Illinois property. The AG's office expects appraisals from licensed Illinois appraisers for Illinois real estate, particularly for residential properties in Cook and Lake counties where values are high and audit scrutiny is elevated.

Illinois probate may still be required. If the decedent owned Illinois real estate solely in their own name — not held in a trust, not in joint tenancy with right of survivorship, not covered by a Transfer on Death Instrument — the property may need to go through Illinois ancillary probate in the appropriate circuit court. This is separate from the primary probate proceedings in the decedent's home state. Ancillary probate requires retaining an Illinois probate attorney.

The 120-day vehicle rule. If the decedent had vehicles registered in Illinois (or vehicles physically located in Illinois long-term), the executor has 120 days to transfer title through the Illinois Secretary of State using Form VSD-190. Missing this window complicates the transfer and can delay insurance coverage.

Remote e-filing challenges. Illinois courts mandate e-filing for probate matters. Out-of-state executors who are unfamiliar with the Illinois e-filing system sometimes attempt to mail documents and have their petitions rejected. An Illinois probate attorney is the practical solution for court filings.

When Illinois Tax Liability Can Be Minimized

For non-resident decedents who were planning ahead, certain structures reduce Illinois estate tax exposure on Illinois property:

Living trusts: Illinois real estate held in a revocable living trust at the time of death bypasses ancillary probate. It does not avoid the estate tax calculation, but it avoids the court process.

Transfer on Death Instruments (TODIs): Illinois recognizes TODIs for real estate. A properly recorded TODI transfers the property to a named beneficiary at death without probate. However, the value still counts in the estate for estate tax calculation purposes.

Community property trust (if applicable): Illinois permits community property trusts, which can produce a full double step-up in basis on appreciated real estate. For non-residents whose home state also recognizes community property structures, this may offer capital gains benefits even if the estate tax exposure remains.

These planning strategies must be implemented before death. Post-death, the executor's options are limited to ensuring the Form 700 allocation calculation is accurate and that all exemptions and deductions the estate is entitled to are properly claimed.

For comprehensive guidance on managing the Illinois estate tax as an out-of-state executor — including the Form 700 filing, allocation worksheet, fiduciary income tax, and certificate of discharge process — the Illinois Final Tax & Estate Tax Guide is designed specifically for executors navigating these cross-state complexities.

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