IL-KY Tax Reciprocity 2026

IL-KY reciprocity serves the far-southern Illinois / western Kentucky corridor (Metropolis IL - Paducah KY) plus remote workers employed across the state line.

Quick answer: Yes - IL and KY have a reciprocal tax agreement. IL residents working in KY file form 42A809 (KY Certificate of Nonresidence) and pay only IL tax. KY residents working in IL file IL-W-5-NR and pay only KY tax.

How It Works Both Directions

ScenarioForm To FileResult
Live IL, work KY42A809 (to skip KY)No KY withholding. Pay IL tax only.
Live KY, work ILIL-W-5-NR (to skip IL)No IL withholding. Pay KY tax only.

Worked Example

Tyler lives in Metropolis IL, works in Paducah KY, earns $58,000. With reciprocity: he files 42A809 with his KY employer. KY withholds $0 state tax. IL withholds ~$2,871 (4.95% flat). He files only an IL-1040. Note: Paducah, like many KY cities, levies a local occupational license fee on wages earned inside city limits - that local fee is NOT covered by reciprocity and is still withheld.

Step-by-Step: Claim the Exemption

  1. Download the work-state exemption form (KY form 42A809 for IL-residents-working-in-KY; IL form IL-W-5-NR for KY-residents-working-in-IL).
  2. Fill in name, SSN, home address (must be in the reciprocity state), and current date.
  3. Submit to HR/payroll at your employer.
  4. Verify on your next paystub that work-state tax withholding is $0.
  5. Update your home-state W-4 to make sure you withhold enough for full income tax.
  6. File only a resident return in your home state next April (unless you have non-wage work-state income).

OBBBA 2026 Note

OBBBA 2026 (One Big Beautiful Bill Act) raised the federal SALT cap to $40,000. This matters for reciprocity commuters who itemize: your full home-state income tax is now more likely to be fully deductible on federal Schedule A, making the state-level tax difference between your home and work state a real after-tax driver of commute value. Check each state rate: IL top rate 4.95% flat, KY top rate 3.5% flat (2026).

FAQ

Which form does an Illinois resident working in Kentucky file?

File KY form 42A809 (Certificate of Nonresidence) with your Kentucky employer. KY state withholding stops; you withhold Illinois tax instead. Re-file if your home address changes.

Which form does a Kentucky resident working in Illinois file?

File IL form IL-W-5-NR (Employee’s Statement of Nonresidence in Illinois) with your Illinois employer. Illinois withholding stops and you pay only Kentucky’s 3.5% flat tax (2026 rate).

Does IL-KY reciprocity cover Kentucky local occupational taxes?

No. KY cities and counties (Paducah, Louisville, Lexington, and many others) levy occupational license fees on wages earned within their boundaries. These local payroll taxes apply to nonresidents and are NOT covered by state reciprocity.

What if Kentucky tax was withheld before I filed 42A809?

File KY form 740-NP-R (Kentucky Income Tax Return - Nonresident Reciprocal State) for that year to claim a full refund of the KY withholding. Then file your IL-1040 as normal and submit 42A809 to payroll going forward.

Does reciprocity apply to 1099 contractor income?

No. Reciprocity covers W-2 wages and salaries only. Self-employment income an IL resident earns from KY sources is KY-source income requiring a KY nonresident return (740-NP), with a credit claimed on the IL return.

Model Your Take-Home

See exact post-reciprocity paycheck with IL or KY withholding.

Paycheck Calculator →

Run the numbers for each state: Illinois Income Tax Calculator · Kentucky Income Tax Calculator

Other reciprocity pairs:
IL-MI · IN-MI · IN-WI · MI-WI · MI-MN · MN-ND · Full matrix

Tax calculations are estimates for educational and informational purposes only. This site does not provide tax, legal, or financial advice. Tax laws change frequently. Always consult a qualified tax professional for advice specific to your situation. Data sourced from IRS publications and official state tax authority websites.

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