Moved from Illinois to Oklahoma Mid-Year: Which State Tax Returns Do You File?
Answer
You file two part-year returns. Illinois taxes the income you received while you lived there, Oklahoma taxes the income you received after the move, and each state prorates your deductions and credits to its own slice of the year. The date you changed domicile is the dividing line.
Last verified
Part-year returns are designed so that neither state taxes the whole year. The risk is not double taxation by default; it is misassigning income received near the move date, and losing the proration on deductions and credits.
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 · OklahomaForm 511-NR
File a Oklahoma part-year return covering the months you lived in Oklahoma. A part-year resident of Oklahoma reports the income received while a Oklahoma resident, plus any Oklahoma-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 | Oklahoma | |
|---|---|---|
| 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 511-NR |
| Part-year return | Form IL-1040 with Schedule NR | Form 511-NR |
| Credit for other-state tax | Schedule CR | Form 511-TX |
| Nonresident safe harbour | 30 days | None published |
| Local income tax | No | No |
| Revenue department | Illinois Department of Revenue | Oklahoma Tax Commission |
| Last verified |
The other direction
Reversing the commute does not always reverse the answer. Living in Oklahoma 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 → OklahomaBoth states — credit offsets the double tax
- Remote worker: Illinois → OklahomaHome state only
- 1099 contractor: Illinois → OklahomaHome state, plus the client state if you work there
Other Illinois pairs
Questions people actually ask
I moved from Illinois to Oklahoma mid-year. Do I have to file in both states?
You file two part-year returns. Illinois taxes the income you received while you lived there, Oklahoma taxes the income you received after the move, and each state prorates your deductions and credits to its own slice of the year. The date you changed domicile is the dividing line.
How do I split my income between Illinois and Oklahoma?
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 Oklahoma 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 Oklahoma rules on this page were last checked against Illinois Department of Revenue and Oklahoma Tax Commission 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
- Oklahoma Tax Commission — individual income taxaccessed 2026-08-07