Residency Migration Reference
Moving from Illinois to Colorado: Residency, Taxes, and What to Prove
The top income tax rate drops from 4.95% (flat) in Illinois to 4.40% in Colorado. Establishing Colorado residency correctly is what protects that benefit.
Residency Tests Side by Side
Neither Illinois nor Colorado relies on a simple statutory day-count threshold. Both apply a facts-and-circumstances or closest-connections style test, so day counting alone will not settle a residency question in either direction.
| Factor | Illinois | Colorado |
|---|---|---|
| Statutory Residency Test | Illinois has no statutory residency test of the New York or Minnesota type: no bright-line day count and no permanent place of abode prong. 35 ILCS 5/1501(a)(20)(A) defines a resident as an individual '(i) who is in this State for other than a temporary or transitory purpose during the taxable year; or (ii) who is domiciled in this State but is absent from the State for a temporary or transitory purpose during the taxable year.' Those are the only two routes to Illinois residency for an individual. Cain v. Hamer, 2012 IL App (1st) 112833, shows how far that departure from a day count runs: snowbird retirees who spent 1,666 days in Illinois against 1,700 in Florida across 1996 through 2004, an average well above 183 Illinois days a year, were held not to be Illinois residents. Day counts matter in Illinois as evidence of purpose and as inputs to the administrative presumptions, not as a threshold that decides residency by itself. | Under Colorado Department of Revenue Rule 39-22-103(8)(a), a natural person is a Colorado resident if either domiciled in Colorado or the person satisfies the six-month rule: maintaining a permanent place of abode in Colorado and spending, in the aggregate, more than six months of the tax year in Colorado. A permanent place of abode is any place a person has a possessory right to live, including a leased apartment or an employer-paid apartment the person actually pays for and returns to on days off; a motel room or an RV camp lot without hookups generally does not qualify. |
| Domicile Test | Illinois follows the traditional common-law domicile standard under 86 Ill. Adm. Code 100.3020: domicile is the place a person intends as their true, fixed, permanent home, and to which they intend to return whenever absent. A person can have only one domicile at a time, and it continues until a new one is established through both physical presence in the new location and demonstrated intent to abandon Illinois as the permanent home. The Department of Revenue looks at where a person votes, holds a driver's license and registers vehicles, banks, keeps professional relationships (doctor, lawyer, accountant), works, houses family, and belongs to clubs or religious institutions; no single factor controls. | Colorado's domicile rule defines domicile as a place of abode combined with the present intention of returning after any absence, regardless of how long the absence lasts. A person can have only one domicile at a time (with a narrow exception for genuine seasonal dual-domicile arrangements), domicile continues until affirmatively changed, and the burden of proving a change rests on the person asserting it. The regulation lists 18 non-exclusive indicia the Department weighs, including prior domicile, length of time in the new place, spouse/dependent location, driver's license and vehicle registration jurisdiction, voter registration, employment location, government benefits received, mailing address for financial documents, professional licenses, prior-year filing positions, and even social media statements of residency; no single factor controls. |
| Day Count Threshold | No fixed threshold | No fixed threshold |
| Any Part of a Day Rule | Not applicable in the statutory sense, because Illinois has no day-count threshold for an individual to cross. There is no any-part-of-a-day rule to apply. Days still get counted in Illinois practice, both because 86 Ill. Adm. Code 100.3020(f) presumes residency above nine months in the aggregate and presumes continued residency where an individual is present in Illinois more days than in any other state, and because the Department of Revenue's audit division reconstructs presence from credit card, toll, and travel records to test whether time in Illinois was temporary or transitory. | The regulation text sets the threshold as 'more than six months' rather than a codified exact day count, so practitioners generally treat it as 183-plus days. The published rule does not spell out an explicit any-part-of-a-day counting convention the way New York's does; absent that guidance, taxpayers close to the line should assume any day with Colorado presence could be counted and keep contemporaneous records. |
| Presumptions | 86 Ill. Adm. Code 100.3020(f) supplies four rebuttable presumptions in place of a statutory day test. An individual who spends in the aggregate more than nine months of any taxable year in Illinois is presumed to be a resident. An individual absent from Illinois for one year or more is presumed to be a nonresident. An individual receiving a homestead exemption on Illinois property under 35 ILCS 200/15-175 is presumed to be an Illinois resident. And an Illinois resident in one year is presumed to be a resident the following year 'if he or she is present in Illinois more days than he or she is present in any other state.' The presumptions 'are not conclusive and may be overcome by clear and convincing evidence to the contrary,' with the rule listing acceptable rebuttal evidence including location of spouse and dependents, voter and vehicle registration, driver's license, filing a resident return elsewhere, home ownership or rental agreements, the permanent or temporary nature of work assignments, location of professional licenses, location of medical providers, accountants and attorneys, club memberships and participation, and telephone or other utility usage over a duration of time. | The place where a person currently lives is presumed to be their current domicile, and once domicile is established it is presumed to continue. Spouses are presumed to share a domicile until separated. A person who lives in a motorhome and owns no real property elsewhere is treated as a full-year Colorado domiciliary if their permanent ties are here and they spend more aggregate time in Colorado than anywhere else; conversely, someone who owns a home in another state but travels to Colorado seasonally is not treated as a Colorado domiciliary absent other factors. |
| Safe Harbors | None published | None published |
Leaving Illinois
Illinois is not in the top tier of aggressive exit-audit states the way New York or California are, but the Department of Revenue does examine departing high earners, especially where a large capital gain or business sale occurred near the claimed move date, or where the taxpayer kept an Illinois home, spouse, or business presence after claiming nonresidency. Auditors reconstruct day counts using credit card statements, toll records, airline records, and utility usage, and they cross-check the General Homestead Exemption against a claimed out-of-state domicile.
Trailing Income
Illinois does not have a convenience-of-the-employer rule, so a former resident who telecommutes for an Illinois employer from another state generally is not taxed by Illinois on those wages solely because the employer is based in Illinois; sourcing follows where the work is actually performed. Illinois does tax nonresident income that is Illinois-source, including compensation for services actually performed in Illinois, gain on the sale of Illinois real property, and a departing resident's share of Illinois business income allocated under the state's apportionment rules for the period they were still a resident or doing business in the state.
Part-Year Filing
Form IL-1040 together with Schedule NR, Nonresident and Part-Year Resident Computation of Illinois Tax, is used for the year someone moves into or out of Illinois. Schedule NR allocates income between the Illinois-resident portion of the year and the nonresident portion, and computes an Illinois tax based only on Illinois-source and Illinois-period income.
Enforcement Methods
Common Exit Mistakes
Establishing Colorado Residency
| Action | Agency | Deadline |
|---|---|---|
| Get a Colorado driver's license | Colorado Division of Motor Vehicles | no fixed statutory day count for the license itself, but establishing residency (90 consecutive days, gainful employment, or operating a business in Colorado) triggers the requirement |
| Register vehicles in Colorado | Colorado DMV / county motor vehicle office | within 90 days of establishing residency under the Colorado Registration Fairness Act |
| Register to vote | Colorado Secretary of State / county clerk | register anytime; Colorado also allows registration in person at a voter service and polling center through Election Day |
Declaration of Domicile
Colorado has no formal declaration-of-domicile filing comparable to Florida's. Domicile is shown entirely through conduct and the 18-factor indicia list in Rule 39-22-103(8)(a): driver's license, vehicle registration, voter registration, spouse/dependent location, employment, professional licenses, mailing address for financial documents, and prior-year filing positions among them.
Homestead
Colorado's homestead exemption (C.R.S. §38-41-201) automatically protects up to $250,000 of equity in an owner-occupied home from most creditors, rising to $350,000 if an owner, spouse, or dependent is 60 or older or disabled; no filing is required. Separately, the Senior Property Tax Exemption (65+, 10 consecutive years of ownership and occupancy) exempts 50% of the first $200,000 of actual value and is a strong domicile-evidence factor precisely because it demands a decade of continuous residence, which the Department or a prior home state can cross-check against a claimed departure date.
Voter Registration
No advance deadline: Colorado permits registration up through and including Election Day at a voter service and polling center, in addition to standard mail and online registration. https://www.sos.state.co.us
Vehicle Registration Deadline
90 days
New Resident Tax Traps
Colorado taxes a new resident's worldwide income from the date Colorado domicile begins, requiring the DR 0104PN apportionment for the year of the move. Because domicile in Colorado can be established on the very first day of physical presence if intent is clear, a person who moves mid-year with a firm intent to stay does not get a grace period; the six-month rule is a separate, independent trigger that can make someone a resident even without domicile if they keep a permanent Colorado abode.
What Changes on Tax
Illinois Top Rate
4.95% (flat)
Colorado Top Rate
4.40%
Moving from Illinois to Colorado drops the top marginal income tax rate from about 4.95% to about 4.4%, a reduction of roughly 0.55 percentage points.
Withholding Reciprocity
Illinois and Colorado do not have a wage-withholding reciprocity agreement with each other, so this move follows ordinary source-state and resident-state filing rules rather than a reciprocity exception.
Community Property Transition
Illinois and Colorado both use common law, equitable-distribution marital property rules, so no community property transition applies to this move.
Beyond Income Tax
Illinois
Capital gains: No preferential rate. Capital gains are taxed as ordinary income at the same 4.95% flat rate as wages.
Estate or inheritance tax: Illinois has an estate tax with a $4 million exemption per estate that is not indexed for inflation and is not portable between spouses. Rates are graduated from roughly 0.8% up to 16% on the amount above the exemption. There is no separate inheritance tax.
Property tax: Illinois has the highest statewide effective property tax rate in the country, around 1.92% of home value, more than double the national median. The General Homestead Exemption reduces the taxable assessed value of an owner-occupied principal residence by up to $10,000 in Cook County, $8,000 in counties bordering Cook, and $6,000 elsewhere.
Sales tax: State base rate is 6.25%, but local home-rule and county taxes push combined rates as high as 11.5% in parts of Cook, Kane, and Warren counties; the effective statewide average is closer to 8.9%.
Colorado
Capital gains: Taxed as ordinary income at the flat 4.40% rate. Colorado once allowed a broad $100,000 capital gain subtraction for qualifying property held five-plus years, but for tax years commencing on or after January 1, 2022 that subtraction was narrowed to apply only to capital gains recognized by farmers who file federal Schedule F on the sale of agricultural real property. Nearly everyone else pays the full flat rate on gains.
Estate or inheritance tax: None. Colorado has no estate tax and no inheritance tax.
Property tax: Effective rate is roughly 0.50% of value, among the lowest in the country. Colorado's Senior Property Tax Exemption is a targeted homestead-style break, not a general portability system: it exempts 50% of the first $200,000 of actual value for owners 65 and older who have owned and occupied the home for at least 10 consecutive years, funded by state reimbursement to counties when the legislature appropriates it.
Sales tax: 2.90% state rate, with average combined state-and-local rates around 7.89% once city, county, and special-district taxes are layered on.
Who This Move Applies To
Travel Nurses
In Illinois
Illinois has no statutory day-count test to trip, so a travel nurse not domiciled in Illinois does not become an Illinois resident merely by crossing a day threshold on a long assignment. What creates exposure instead is the temporary or transitory question and the 100.3020(f) presumptions: an assignment structured as a series of renewals that keeps a nurse in Illinois more than nine months of a year, or more days than in any other state, supports a presumption of residency that must be rebutted by clear and convincing evidence, and the permanent or temporary nature of the work assignment is named in the rule as relevant evidence. The more common Illinois exposure is the reverse pattern, where a nurse claims a Florida or Texas tax home but actually lives in and pays Illinois-area rent for most of the year; Illinois-source wages for days actually worked in Illinois are taxable to any nonresident nurse regardless of claimed tax home.
In Colorado
Denver, Colorado Springs, and the Front Range hospital systems make Colorado a significant travel-nurse market. A nurse whose actual domicile is Colorado and who takes Colorado contracts is simply taxed as a resident. A nurse who claims a Colorado tax home while working assignments in other states needs a genuine, regularly used, duplicated-expense Colorado residence; the same indicia list the Department applies to ordinary domicile disputes (driver's license, voter registration, time actually spent) applies to a nurse's claimed tax home, and a thin paper trail risks the same stipend-to-wages reclassification travel nurses face in every state.
Professional Athletes
In Illinois
Illinois taxes nonresident professional athletes on a duty-day basis: Illinois-source income equals total compensation multiplied by the ratio of duty days in Illinois (games, practices, mandatory team functions) to total duty days for the season; mere travel through Illinois without a game or team event does not create a duty day. This applies to visiting teams playing the Bears, Bulls, Blackhawks, White Sox, and Cubs, and Illinois is regarded by practitioners as an aggressive, well-enforced jock-tax state that historically extended the tax reciprocally to any state that taxed Illinois-based athletes.
In Colorado
Colorado is home to the Broncos, Nuggets, Rockies, and Avalanche, and nonresident athletes on visiting teams owe Colorado tax on the duty days they spend in the state under standard apportionment against total season duty days. Because Colorado's rate is a flat 4.40% with no separate capital-gains carve-out, the jock-tax math is simpler than in graduated-rate states, but the liability is real and applies to every visiting team that plays a game in Denver.
Snowbirds, Long Visitors, and RVers
In Illinois
The Illinois snowbird risk runs entirely through the 100.3020(f) presumptions, not through a day threshold. A retiree who keeps the Illinois house and spends more than nine months there risks the nine-month presumption of residency, and a former Illinois resident is presumed to still be one in the following year if present in Illinois more days than in any other state, which is a comparison a snowbird splitting a year can lose well short of any traditional threshold. The favorable counterweight is Cain v. Hamer, 2012 IL App (1st) 112833, where retirees who split time nearly evenly (1,666 Illinois days against 1,700 Florida days across 1996 through 2004) were held nonresidents, with the court weighing nexus evidence such as Florida licenses, voter registration, a Florida declaration of domicile, club spending, and credit card data showing 73% of expenditures and 61% of transactions outside Illinois. Illinois's General Homestead Exemption is a specific cross-check point if a person claims Florida domicile but keeps the Illinois exemption active.
In Colorado
Colorado's scenario runs in both directions. Wealthy buyers in Aspen, Vail, Telluride, and other mountain resort towns who keep a primary domicile elsewhere need to track aggregate days against the six-month, permanent-place-of-abode threshold, since a leased or owned ski home plainly qualifies as a permanent place of abode. Separately, Colorado's own domiciliaries who spend winters in Arizona or Florida remain presumed Colorado domiciliaries under the regulation's continuing-domicile presumption unless they affirmatively establish a new domicile elsewhere, so simply wintering out of state does not by itself cut Colorado ties.
Remote Workers
In Illinois
Illinois has no convenience-of-the-employer rule. A nonresident who works remotely from another state for an Illinois-based employer is generally not taxed by Illinois on those wages, because Illinois sources employee compensation to where the services are physically performed, not to the employer's location. This makes Illinois meaningfully less sticky for remote workers than New York or a handful of other convenience-rule states.
In Colorado
Colorado has no convenience-of-employer rule: a nonresident performing all work physically outside Colorado for a Colorado-based employer is not Colorado-taxed on those wages solely because the employer is headquartered here. Colorado has been a significant landing spot for remote workers relocating from California, Texas, and the coasts since 2020, and the state has no reciprocal withholding agreements with any other state, so a genuine mid-year move still requires the DR 0104PN part-year split rather than a simple withholding switch.
Military
In Illinois
Illinois follows the federal Servicemembers Civil Relief Act and Military Spouses Residency Relief Act. A servicemember whose home of record is Illinois remains an Illinois domiciliary for tax purposes regardless of duty station unless they take affirmative steps to change domicile, while a servicemember stationed in Illinois on orders, and their qualifying spouse, does not become an Illinois resident solely because of the posting, and military pay is not Illinois-source income for a nonresident servicemember stationed there.
In Colorado
Colorado follows the federal Servicemembers Civil Relief Act and Military Spouses Residency Relief Act. A service member stationed in Colorado on orders does not become a Colorado domiciliary from the posting alone, and neither does an accompanying spouse who elects to keep the service member's home-state domicile under MSRRA. Colorado also offers a military retirement subtraction that interacts with, but does not simply duplicate, the general pension and annuity subtraction.
Airline Crew
In Illinois
Federal law (49 U.S.C. §40116) limits states to taxing airline employee compensation only in the employee's state of residence and any state where more than 50% of pay is earned. This protects flight crew based at O'Hare or Midway who are domiciled outside Illinois from having their full compensation pulled into Illinois taxation solely because their duty station is in Illinois.
In Colorado
Denver International Airport (DEN) is a major hub for United Airlines and a large Southwest Airlines operation, giving Colorado a meaningful resident and crew-base airline population. Federal law (49 U.S.C. §40116) limits state taxation of air carrier employees to their state of residence and any state where they earn more than 50% of their pay, which matters directly for DEN-based crew who fly national routes.
Tools for This Move
Illinois to Colorado FAQ
Does Illinois have a 183-day rule like New York or Minnesota?+
No. This is the single most common misconception about Illinois residency. 35 ILCS 5/1501(a)(20) contains no day-count threshold and no permanent place of abode prong; a resident is someone in Illinois for other than a temporary or transitory purpose, or an Illinois domiciliary absent for a temporary or transitory purpose. What Illinois has instead are the rebuttable presumptions in 86 Ill. Adm. Code 100.3020(f), including a presumption of residency above nine months in the aggregate and a presumption that a prior-year resident remains one if present in Illinois more days than in any other state. The practical difference is real in both directions: crossing 183 Illinois days does not by itself make you a resident, and staying under 183 does not by itself make you a nonresident.
Does Colorado use the 183-day rule?+
Not exactly as codified. Colorado's six-month rule under Department Rule 39-22-103(8)(a) makes you a statutory resident if you keep a permanent place of abode in Colorado and spend more than six months (commonly treated as 183-plus days) here in the aggregate during the year, separate from and in addition to the ordinary domicile test.
If I move to Florida but keep my Chicago condo, will Illinois still tax me?+
Keeping the condo does not by itself make you taxable, because Illinois has no permanent place of abode test that a retained condo could trigger. The risk runs through purpose and presumptions instead. If you spend more than nine months of the year in Illinois, or simply more days there than in any other state after a year as an Illinois resident, the Department gets a presumption of residency you can rebut only by clear and convincing evidence. Continuing to claim the General Homestead Exemption on the condo is worse than the condo itself, since that alone creates its own presumption of Illinois residency and is a cross-check Illinois auditors run directly against a claimed out-of-state domicile.
How does Colorado decide if I'm still domiciled here after I move?+
Colorado weighs 18 non-exclusive factors, including where your driver's license, vehicle registration, and voter registration are, where your spouse and dependents live, your employment location, your mailing address for financial documents, and even public statements of residency. No single factor controls, and once Colorado domicile is established it's presumed to continue until you affirmatively establish a new one elsewhere.
Does Illinois have a convenience-of-the-employer rule for remote workers?+
No. Illinois sources employee wages to where the work is physically performed, not to where the employer is headquartered. A nonresident who works remotely from another state for a Chicago-based employer generally is not taxed by Illinois on those wages, which is a meaningful difference from convenience-rule states like New York, and it means remote workers face less Illinois exposure after moving away than they might expect.
I bought a place in Aspen but I'm domiciled in Texas. Do I owe Colorado tax?+
Not from domicile alone, since a person who owns a home in another state but visits Colorado seasonally isn't treated as a Colorado domiciliary absent other factors. But the ski home is a permanent place of abode, so if your aggregate Colorado days exceed six months in a year, the separate statutory six-month rule makes you a Colorado resident regardless of your Texas domicile.
How do I file my Illinois taxes for the year I move out of state?+
File Form IL-1040 together with Schedule NR, the Nonresident and Part-Year Resident Computation of Illinois Tax. Schedule NR splits your income between the period you were an Illinois resident, which is taxed in full, and the period after you became a nonresident, when only Illinois-source income is taxed. Skipping Schedule NR and simply filing as a full-year nonresident in your move year is a common and easily flagged mistake.
What form do I file if I only lived in Colorado part of the year?+
Form DR 0104 along with the DR 0104PN, the Part-Year Resident/Nonresident Tax Calculation Schedule, which prorates your Colorado tax to income earned while you were a Colorado resident plus any Colorado-source income earned before you arrived or after you left.
I work in Illinois but live in Wisconsin. Do I have to file two state returns?+
Illinois has reciprocity with Wisconsin, Iowa, Kentucky, and Michigan, so a Wisconsin resident working in Illinois generally does not owe Illinois tax on those wages and should not have Illinois tax withheld; instead, only Wisconsin taxes that income. If Illinois tax was withheld in error, you file for a refund from Illinois rather than claiming a credit, and you report the income on your Wisconsin return as usual.
Does Colorado tax Social Security and retirement income?+
Yes, but with a growing subtraction. Through 2025 the pension and annuity subtraction (which covers qualifying Social Security, pensions, and certain IRA income) is capped at $20,000 for filers 55 to 64 and $24,000 for filers 65 and older. Starting with tax year 2026, Colorado removes that cap entirely, letting any individual subtract their full qualifying pension and annuity income.
Will keeping the homestead exemption on my Illinois house hurt me if I claim Florida residency?+
Yes, it's a direct contradiction auditors specifically look for. The General Homestead Exemption requires the property to be your owner-occupied principal residence as of January 1, so continuing to receive it while filing as an Illinois nonresident and claiming Florida domicile undercuts your own position. If you've genuinely moved, removing the exemption is one of the concrete steps that supports your new domicile claim.
Does Colorado have a capital gains tax?+
Capital gains are taxed as ordinary income at the flat 4.40% rate. Colorado used to allow a broad $100,000 subtraction for long-held qualifying property, but since tax year 2022 that subtraction only applies to farmers who file federal Schedule F on the sale of agricultural real property, so most taxpayers get no special break on gains.
Planning the reverse move?
Colorado to Illinois
Moving the other direction is a different fact pattern, not a mirror image. Establishing Illinois residency has its own tests, deadlines, and audit posture.
Start with the Illinois residency guideAlso Consider, Leaving Illinois
Illinois to Colorado Reading
Reviewed Against 31 Primary Sources
ResidencyIQ organizes public residency research into a reviewable reference. It does not provide legal or tax advice. Consult a qualified professional before making a residency decision.
Start your record
Build your Illinois to Colorado mobility map.
Start with a free map, document your center of life, then upgrade when you need evidence, advisor collaboration, and audit-ready reporting.
Create Free Mobility Map