Moved from Kansas to Illinois Mid-Year: Which State Tax Returns Do You File?
Answer
You file two part-year returns. Kansas taxes the income you received while you lived there, Illinois 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
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 · KansasForm K-40 with Schedule S Part B
File a Kansas part-year return covering the months you lived in Kansas. A part-year resident of Kansas reports the income received while a Kansas resident, plus any Kansas-source income received during the rest of the year, and prorates the deductions and credits to the residency period.
- 2Part-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.
The two states, side by side
| Kansas | Illinois | |
|---|---|---|
| Taxes wages | Yes — graduated | Yes — flat |
| Reciprocity partners | None | 4 (Form IL-W-5-NR) |
| Convenience rule | No | No |
| Nonresident return | Form K-40 with Schedule S Part B | Form IL-1040 with Schedule NR |
| Part-year return | Form K-40 with Schedule S Part B | Form IL-1040 with Schedule NR |
| Credit for other-state tax | Form K-40 (credit for taxes paid to other states) | Schedule CR |
| Nonresident safe harbour | None published | 30 days |
| Local income tax | No | No |
| Revenue department | Kansas Department of Revenue | Illinois Department of Revenue |
| Last verified |
The other direction
Reversing the commute does not always reverse the answer. Living in Illinois and working in Kansas 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: Kansas → IllinoisBoth states — credit offsets the double tax
- Remote worker: Kansas → IllinoisHome state only
- 1099 contractor: Kansas → IllinoisHome state, plus the client state if you work there
Other Kansas pairs
Questions people actually ask
I moved from Kansas to Illinois mid-year. Do I have to file in both states?
You file two part-year returns. Kansas taxes the income you received while you lived there, Illinois 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 Kansas and Illinois?
By when you received it, measured against the date your domicile actually changed. Income received while you were a Kansas resident belongs on the Kansas return and income received afterwards on the Illinois 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 Kansas and Illinois rules on this page were last checked against Kansas Department of Revenue and Illinois 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.
- Kansas Department of Revenue — individual income taxaccessed 2026-08-07
- Illinois Department of Revenue — individual income taxaccessed 2026-08-07