Illinois is the quiet corner of the high-tax exodus story. It does not make the headlines the way California and New York do. Its top income tax rate looks restrained next to New York City’s or New Jersey’s. But for a wealthy Illinois resident running the math honestly, the picture is as bad as anywhere in the country — and in some respects worse.
Illinois taxes income at a flat 4.95% with no preferential rate for capital gains. It taxes estates above $4 million at rates climbing to 16% — an exemption that was set by statute, is not indexed to inflation, and sits roughly ten million dollars below the federal exemption. Its property taxes are the second highest in the United States, trailing only New Jersey, with effective rates in Cook County suburbs regularly exceeding 2.5%. Underneath all of this sits a pension system with $140+ billion in acknowledged unfunded liabilities and a fiscal trajectory that makes the 4.95% number look less like a ceiling and more like a floor.
Florida has none of these things. Here is what the move actually saves, what Illinois does about it, and what it takes to do it correctly.
What You Actually Save
Illinois income tax is not the highest in the nation on paper. But three things compound to make the actual savings from a Florida move larger than the 4.95% sticker rate suggests.
The flat rate applies from the first dollar to the last. Illinois does not graduate its income tax. The 4.95% rate applies to essentially all of your income — ordinary income, interest, dividends, capital gains, pass-through business income. There is no preferential treatment for long-term capital gains, no exemption for qualified dividends at the state level, no reduced rate on Section 1202 stock gains. A $10 million capital gain from the sale of a founder’s equity position is taxed the same as a $10 million salary. The flat structure is written into the Illinois Constitution, Article IX, Section 3: “A tax on or measured by income shall be at a non-graduated rate.” Graduated brackets would take a constitutional amendment. A higher flat rate would not.
The Personal Property Replacement Tax sits on top. Income passing through partnerships, S-corporations, and certain trusts is subject to an additional Illinois levy — 1.5% for most pass-through entities and 2.5% for corporations. For business owners and investors receiving distributions through pass-through structures, the effective state-level rate on that income is 6.45%, not 4.95%.
The estate tax runs in parallel. Illinois’s estate tax is one of the most punitive in the country for estates between $4 million and the federal exemption. The income tax paid year by year is only part of the lifetime state tax cost. The estate tax settles the rest.
Put that together, and the annual income tax savings from a Florida move for Illinois residents at different income levels looks roughly like this:
| Annual Income | Illinois Tax (est.) | Florida Tax | Annual Savings |
|---|---|---|---|
| $500,000 | ~$25,000 | $0 | ~$25,000 |
| $1,000,000 | ~$50,000 | $0 | ~$50,000 |
| $2,000,000 | ~$99,000 | $0 | ~$99,000 |
| $5,000,000 | ~$248,000 | $0 | ~$248,000 |
These are pre-Replacement-Tax numbers for ordinary W-2 income. For business owners whose income flows through pass-through entities, add roughly 30% to the Illinois column. For estates of meaningful size, the estate tax savings alone — separately discussed below — can dwarf the annual income tax savings.
Selling Assets Around the Move
When a gain is realized matters as much as how large it is. Illinois allocates every item of a full-year resident’s income to Illinois. A part-year resident’s income is allocated to Illinois for the part of the year spent as a resident; for the rest of the year, only the Illinois-source items named in Sections 302 to 304 are allocated (35 ILCS 5/301).
For a nonresident, 35 ILCS 5/303 sorts capital gains by asset type:
- Illinois real estate. Gain on real property located in Illinois is Illinois income, wherever the seller lives.
- Stocks, bonds, and other intangibles. Gain is allocable to Illinois only if the taxpayer’s commercial domicile is in Illinois at the time of the sale.
- S-corporation shares and partnership interests. Gain is allocable to Illinois if the entity is taxable in Illinois, in proportion to the entity’s average Illinois apportionment factor for the year of sale and the two years before it. Investment partnerships are excepted.
The last rule is the one founders miss. A Florida domicile does not by itself take the sale of an Illinois operating business out of Illinois tax.
The $4 Million Estate Tax Trap
This is the piece of Illinois tax law that does the most damage to wealthy families and that most non-Illinois tax advisors are unprepared for.
Illinois decoupled its estate tax from the federal system years ago. The federal estate tax exemption in 2026 sits near $15 million per person. Illinois’s exemption sits at $4 million. It is set by state statute. It is not indexed to inflation. It has not moved meaningfully in over a decade.
The practical effect is that an estate between $4 million and the federal exemption — an estate that owes zero federal estate tax — can owe Illinois estate tax calculated at graduated rates climbing to 16%. For a $10 million estate, the Illinois estate tax bill is roughly $1 million. For a $20 million estate, the Illinois estate tax bill is roughly $2.3 million. None of this is owed at the federal level. It is entirely an Illinois-level cost.
Illinois does not offer portability between spouses. When a spouse dies, any unused Illinois exemption is lost. A married couple cannot combine their $4 million exemptions into an $8 million shield at the second death unless credit-shelter trusts are structured correctly while both spouses are alive. The planning is available, but it is not automatic, and an estate plan drafted without Illinois-specific attention can waste the first-to-die spouse’s exemption entirely.
Florida has no estate tax. Florida’s constitution prohibits it, and a change would require a constitutional amendment — not a legislative vote. The estate tax liability for a Florida-domiciled decedent owning non-Illinois assets is zero at the state level. The federal exemption is the only exemption that matters.
For a wealthy Illinois family, the estate tax savings from a genuine Florida domicile are typically larger in absolute dollar terms than the annual income tax savings. This is particularly true for families whose income is modest relative to their accumulated wealth — founders whose value is locked in appreciated business interests, retirees living off portfolio withdrawals, inheritance recipients holding long-dated positions. For these families, the estate tax is the tax that matters most, and Florida is the strongest answer in the country.
How the Illinois Tax Is Computed
The Illinois estate tax does not have its own rate schedule. The Illinois Estate and Generation-Skipping Transfer Tax Act, 35 ILCS 405/2, defines the tax by reference to the federal state death tax credit as the Internal Revenue Code computed it on December 31, 2001, with an exclusion amount of $4,000,000 for persons dying on or after January 1, 2013.
The Illinois Attorney General, not the Department of Revenue, administers the tax. Its instruction fact sheet sets out the mechanics:
- The $4,000,000 exclusion “is a taxable threshold and not a credit against tax.”
- A Form 700 must be filed if the gross estate, after adjusted taxable gifts, exceeds $4,000,000, whether or not a federal return is required.
- The tax is due nine months after the date of death.
- In the Attorney General’s own example, a $5,000,000 estate of all-Illinois property owes $285,714 in Illinois estate tax and nothing federally.
- “The portability and carry-over of the unused federal exemption to the surviving spouse is inapplicable to the computation and assessment of the Illinois Estate Tax.”
Illinois does allow its own marital deduction election for qualified terminable interest property, separate from any federal QTIP election (35 ILCS 405/2(b-1)).
What a Florida Domicile Removes, and What It Does Not
The statute draws the line by domicile and by asset type (35 ILCS 405/5):
- Illinois resident at death. All transferred property has an Illinois tax situs, including property held in trust, except real or tangible personal property physically situated in another state.
- Nonresident at death. Only real estate and tangible personal property physically situated in Illinois has an Illinois tax situs, including such property held in trust.
For a Florida domiciliary, that means brokerage accounts, retirement accounts, and business interests fall outside the Illinois tax. A Chicago residence, a Lake Forest summer home, Illinois investment real estate, and art or other valuables kept in Illinois do not.
The tax on Illinois property is apportioned, not computed in isolation. Under 35 ILCS 405/3(c), the tax is reduced by the share of the gross estate that has no Illinois situs. The Attorney General’s fact sheet instructs estates to compute a preliminary tax “assuming all assets are located within Illinois,” then multiply it by the ratio of Illinois assets to total assets. Its example: a $5,000,000 estate split evenly between Illinois and Florida owes $142,857 in Illinois estate tax, “even though Florida imposes no State Estate Tax.”
Trusts Written Under Illinois Law
Trusts can keep an Illinois connection after the person who created them leaves. For income tax purposes, 35 ILCS 5/1501(a)(20) treats two kinds of trust as Illinois residents: a trust created by the will of a decedent domiciled in Illinois at death, and an irrevocable trust whose grantor was domiciled in Illinois when the trust became irrevocable. A trust that became irrevocable before the move stays an Illinois resident trust after it.
Property Tax: The Silent Cost
Illinois has the second-highest effective property tax rate in the United States. The statewide effective rate sits near 2% of assessed value, but that average is misleading. Affluent Cook County and collar-county communities regularly produce effective rates above 2.5% on primary residences. A $3 million home in Winnetka, Lake Forest, or Hinsdale can generate an annual property tax bill of $75,000 to $90,000.
For comparison, Florida’s statewide effective property tax rate is roughly 0.8% — less than half of Illinois. A $3 million home in Naples, Palm Beach, or Key Biscayne generates a meaningfully smaller tax bill, and Florida’s homestead exemption provides both a direct reduction and a cap on year-over-year assessed value increases (the “Save Our Homes” 3% cap). For a long-term Florida homeowner, the gap between Illinois and Florida property tax compounds substantially over decades.
The savings on property tax alone, for a high-end Illinois homeowner moving to a comparable Florida residence, is often in the range of $40,000 to $60,000 per year — before any income tax or estate tax consideration enters the picture.
The Illinois Department of Revenue
Illinois runs residency audits, but with a different profile than New York or California. The Illinois Department of Revenue does not operate a dedicated nonresident audit bureau the way New York does. It does not subpoena cell phone records as routinely as California’s Franchise Tax Board. Its audit posture is less systematic and less visible.
That does not mean departures go unexamined. Illinois audits the departures that matter. The state has access to IRS migration data showing who stopped filing as an Illinois resident and when. It reviews federal returns that claim Florida addresses against Illinois records. And in the cases where audit revenue is large enough to justify the resource investment — the high earners, the business owners with Illinois-sourced income, the estates caught between the $4 million and $15 million exemption gap — the Department of Revenue will pursue the question of whether the claimed move was genuine.
The statutory starting point is the definition of “resident” in 35 ILCS 5/1501(a)(20): an individual “who is in this State for other than a temporary or transitory purpose during the taxable year,” or one “who is domiciled in this State but is absent from the State for a temporary or transitory purpose.” The second clause is the one that catches an incomplete move. A person who leaves Illinois for the winter without changing domicile remains a resident. For the estate tax, the same question is asked once, as of the date of death, and the estate of a decedent domiciled in Illinois is itself an Illinois resident under the same definition.
The analysis Illinois uses is standard interstate domicile analysis: the location of your primary residence, the state of your driver’s license and vehicle registrations, where your doctors and dentists are, where your business relationships are centered, where your family is, where you vote, where your valuables and personal property are kept. Illinois looks at the totality of the facts. A move that consists of a changed mailing address and a Florida driver’s license, but leaves the Chicago home furnished and occupied and the Illinois business relationships intact, is a move Illinois will contest.
The statute of limitations for a standard Illinois audit is three years from filing. For substantial underreporting, it extends further. In practice, the records you build in the years immediately after your departure are the records that defend you when the question comes up — often several years after the claimed move date.
The Chicago Commute and Remote Work
Illinois has reciprocity agreements with Iowa, Kentucky, Michigan, and Wisconsin that simplify wage taxation for residents of those states working in Illinois. Florida is not one of those states, and there is no reciprocity relevance for an Illinois-to-Florida move.
Where remote work does matter is in the treatment of Illinois-sourced wages paid to a Florida-domiciled employee. Illinois taxes wages for services performed in Illinois, regardless of the employee’s state of residence. If you establish Florida domicile but continue to perform services at your Illinois employer’s Chicago office for part of the year, those workdays generate Illinois-source wage income subject to Illinois tax at 4.95%, prorated based on the days worked in Illinois versus out.
Unlike New York, Illinois does not have a convenience-of-the-employer rule. Days genuinely worked from your Florida home for an Illinois employer are not attributed to Illinois. This is a meaningful difference — remote workers with Illinois employers who move to Florida are generally able to eliminate Illinois tax on their remote workdays, unlike their New York counterparts.
The practical implication: if you are a Florida-domiciled remote worker with an Illinois employer, maintain careful records of which workdays you spent in Illinois versus Florida. Illinois days produce Illinois source income. Florida days do not. The records matter when your employer issues a W-2 with Illinois wage allocation and you need to reconcile it against actual workdays.
What Florida Offers
The case for Florida over the available alternatives — Texas, Nevada, Tennessee, Wyoming — is both financial and practical.
The tax profile. Florida has no state income tax, no estate tax, no gift tax, no wealth tax, no capital gains tax, and no tax on retirement income. These are not improvements over Illinois. They are the elimination of an entire category of state tax cost.
The stability. Florida’s constitution prohibits a state income tax. Changing it requires a constitutional amendment, not a legislative vote. This is a structurally durable policy — not one that could reverse in the next legislative session. The certainty compounds over decades of life planning.
The geography. Florida is accessible from Chicago via multiple daily nonstop flights to Miami, Fort Lauderdale, Tampa, Orlando, and West Palm Beach. For families who maintain property in Illinois, visit family in the Midwest, or have professional obligations that occasionally require travel back, Florida is a different geographic proposition than Wyoming or Nevada. Life in South Florida does not require severing the Midwestern connection — only restructuring it.
The community. South Florida has decades of history as a destination for Illinois departures. Naples, in particular, has historically been the primary destination for Chicago-area departures — a community so thick with former Midwesterners that the social infrastructure, medical care network, and professional relationships are essentially continuations of what the departing resident had in Illinois. Palm Beach County and Miami-Dade follow similar patterns. The community matters both for quality of life and as evidence of a genuine domicile change when a Department of Revenue audit arrives.
The homestead protection. Florida’s homestead exemption provides some of the strongest creditor protection for primary residence equity of any state in the country. For wealthy individuals navigating business risk, litigation exposure, or the natural liabilities of a high-net-worth life, unlimited homestead protection is a meaningful asset protection benefit layered on top of the tax advantages.
The Practical Timeline
A move from Illinois to Florida is not a one-day event. Done properly, it unfolds over several months.
Day one: establish the Florida home. A real Florida address, owned or leased in your name. Not a relative’s house. Not a PO box. A home where you actually live.
First weeks: the paperwork. Florida driver’s license. Florida vehicle registration. Voter registration change. Declaration of Domicile filed with your county clerk. These are table stakes and need to be done quickly, in the correct order, with the correct supporting documentation.
First months: the financial and professional layer. Update your brokerage, banking, and financial accounts to your Florida address. Have your estate attorney update your will, trust documents, powers of attorney, and health care directives to reflect Florida law and Florida domicile. Update your address with the Social Security Administration, the IRS, and all retirement account custodians.
Ongoing: the life layer. Florida primary care physician, dentist, specialists. Florida club, civic organization, or community involvement. Transfer or resign memberships in Illinois-based organizations where practical.
The entire year: the day count. From the day you claim Florida residency, where you actually are matters. Illinois looks at day counts, not intentions. So does any state where you keep property. Track it continuously, accurately, and in a form that is credible years later.
The file you build during this process — documentation with dates and evidence — is the foundation of your defense if an audit comes. Most departures that fail, fail not because the paperwork was wrong but because the underlying facts did not support the paperwork. The documentation you create as you live your Florida life is what connects the two.
A Note on Consulting a Tax Professional
Everything above is general information. It is not tax or legal advice.
Illinois domicile planning, particularly when an Illinois estate tax question is involved, is fact-specific and high-stakes. The gap between the Illinois $4 million exemption and the federal exemption produces a planning environment that differs substantially from neighboring states and from the federal rules most attorneys default to. An estate plan that works for a Texas or Florida decedent may produce unnecessary Illinois estate tax if applied without Illinois-specific attention.
A CPA and attorney who specialize in interstate domicile planning and Illinois tax law are worth their fees before you make significant moves. A failed domicile claim — or a poorly structured estate plan that wastes an exemption — can produce multi-year, multi-million-dollar cost differentials.
The day count is the part of the puzzle you should manage yourself. It is the most concrete, documentable, and contemporaneous piece of evidence in the entire analysis — and it is the part most Illinois departures handle worst.
Where Southbound Fits
The common failure in Illinois-to-Florida tax moves is documentation. The paperwork gets done. The driver’s license gets issued. The Declaration of Domicile is filed. Then the resident spends the year living their life — some days in Florida, some days in Illinois, some days traveling — and three years later an audit notice arrives asking for a day-by-day account of where they were.
Reconstructing a day count from memory, calendar entries, credit card statements, and flight itineraries is hard. It produces imprecise results. It looks, to an auditor, like what it is: a story assembled after the fact. Contemporaneous GPS records are the opposite — they were created day by day, before the audit was on the horizon, with no incentive to manipulate them.
Southbound builds that record automatically. The app runs in the background on your iPhone, logging whether each day is spent in Florida or outside it, using iOS’s significant-location-change system. It is battery-efficient and passive. No manual check-ins. No discipline required beyond installing the app once.
The Departure Budget — the central feature on the Southbound dashboard — tells you exactly how many days you can still spend outside Florida and remain on track for 183+. For someone maintaining ties to Illinois, traveling for business, or keeping a Midwestern summer home, that number tells you at a glance whether a proposed trip fits your annual plan. There are no December surprises.
Your location data is stored in your personal iCloud account and never touches Southbound’s servers. We cannot see your history. It is yours, and it is private. When the Illinois Department of Revenue asks for documentation of your Florida days — potentially years after your move — you will have a clean, exportable log, recorded by GPS, timestamped continuously from the beginning. That record is the difference between a defensible position and an uncertain fight.
Build the record from day one, before you need it.
This post is for general informational purposes only and does not constitute tax or legal advice. Interstate domicile planning involves complex, fact-specific legal questions and is subject to change. Work with a qualified tax attorney and CPA who specialize in Illinois domicile and estate tax planning before making decisions based on anticipated tax treatment.
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Published Apr 10, 2026