Moved from Illinois to South Dakota Mid-Year: Which State Tax Returns Do You File?
Answer
One return, filed in Illinois. South Dakota levies no personal income tax, so moving there ends your state filing obligation from the date of the move. A Illinois part-year return covers the income you received while you were still a Illinois resident, and that is the whole of it.
Last verified
The clean part of this move is that only one return follows it. The part that catches people is the withholding: Illinois tax should stop when your residency does, and it often does not without a prompt.
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. South Dakota has no wage income tax, so the move ends your state filing obligation.
The two states, side by side
| Illinois | South Dakota | |
|---|---|---|
| Taxes wages | Yes — flat | No |
| Reciprocity partners | 4 (Form IL-W-5-NR) | None |
| Convenience rule | No | No |
| Nonresident return | Form IL-1040 with Schedule NR | Not applicable |
| Part-year return | Form IL-1040 with Schedule NR | Not applicable |
| Credit for other-state tax | Schedule CR | No income tax |
| Nonresident safe harbour | 30 days | Not applicable |
| Local income tax | No | No |
| Revenue department | Illinois Department of Revenue | South Dakota Department of Revenue |
| Last verified |
The other direction
Reversing the commute does not always reverse the answer. Living in South Dakota and working in Illinois gives:One part-year return — the state you moved to.
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 → South DakotaHome state only
- Remote worker: Illinois → South DakotaHome state only
- 1099 contractor: Illinois → South DakotaHome state only — estimated payments
Other Illinois pairs
Questions people actually ask
I moved from Illinois to South Dakota mid-year. Do I have to file in both states?
One return, filed in Illinois. South Dakota levies no personal income tax, so moving there ends your state filing obligation from the date of the move. A Illinois part-year return covers the income you received while you were still a Illinois resident, and that is the whole of it.
How do I split my income between Illinois and South Dakota?
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 South Dakota return. Keep evidence of the move date — a lease, a closing statement, a licence issue date.
How current is this?
The Illinois and South Dakota rules on this page were last checked against Illinois Department of Revenue and South Dakota 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
- South Dakota Department of Revenue — individual income taxaccessed 2026-08-07