Moved from Illinois to Missouri Mid-Year: Which State Tax Returns Do You File?
Answer
Illinois for the first part of the year, Missouri for the rest. Each state's part-year return reports the income received during that state's residency period and prorates the standard deduction, exemptions and credits accordingly. Keep evidence of the date you actually changed domicile.
Last verified
A mid-year move splits the tax year in two, and each state taxes its own half. That is a residency question, so the machinery that governs commuters — reciprocity agreements, convenience rules, nonresident withholding — is beside the point here.
What you file
- 1Part-year return · IllinoisForm IL-1040 with Schedule NR
File a Illinois part-year return covering the months you lived in Illinois. A part-year resident of Illinois reports the income received while a Illinois resident, plus any Illinois-source income received during the rest of the year, and prorates the deductions and credits to the residency period.
- 2Part-year return · MissouriForm MO-1040 with Form MO-NRI
File a Missouri part-year return covering the months you lived in Missouri. A part-year resident of Missouri reports the income received while a Missouri resident, plus any Missouri-source income received during the rest of the year, and prorates the deductions and credits to the residency period.
The two states, side by side
| Illinois | Missouri | |
|---|---|---|
| Taxes wages | Yes — flat | Yes — graduated |
| Reciprocity partners | 4 (Form IL-W-5-NR) | None |
| Convenience rule | No | No |
| Nonresident return | Form IL-1040 with Schedule NR | Form MO-1040 with Form MO-NRI |
| Part-year return | Form IL-1040 with Schedule NR | Form MO-1040 with Form MO-NRI |
| Credit for other-state tax | Schedule CR | Form MO-CR |
| Nonresident safe harbour | 30 days | None published |
| Local income tax | No | Yes |
| Revenue department | Illinois Department of Revenue | Missouri Department of Revenue |
| Last verified |
The other direction
Reversing the commute does not always reverse the answer. Living in Missouri and working in Illinois gives:Two part-year returns.
Same two states, different situation
The withholding answer turns on how you are paid and where the work happens, not only on which two states are involved.
- W-2 commuter: Illinois → MissouriBoth states — credit offsets the double tax
- Remote worker: Illinois → MissouriHome state only
- 1099 contractor: Illinois → MissouriHome state, plus the client state if you work there
Other Illinois pairs
Questions people actually ask
I moved from Illinois to Missouri mid-year. Do I have to file in both states?
Illinois for the first part of the year, Missouri for the rest. Each state's part-year return reports the income received during that state's residency period and prorates the standard deduction, exemptions and credits accordingly. Keep evidence of the date you actually changed domicile.
How do I split my income between Illinois and Missouri?
By when you received it, measured against the date your domicile actually changed. Income received while you were a Illinois resident belongs on the Illinois return and income received afterwards on the Missouri return, with each state prorating your deductions, exemptions and credits to its own part of the year. Keep evidence of the move date — a lease, a closing statement, a licence issue date.
How current is this?
The Illinois and Missouri rules on this page were last checked against Illinois Department of Revenue and Missouri Department of Revenue on 2026-08-07. We re-check the full grid every December after state legislative sessions close, and re-check the convenience-of-the-employer states quarterly because that is where the rules move fastest.
Sources
Every fact above comes from the revenue department that publishes the rule. We do not cite secondary summaries, and we do not restate a figure we could not find at source.
- Illinois Department of Revenue — individual income taxaccessed 2026-08-07
- Missouri Department of Revenue — individual income taxaccessed 2026-08-07