Moved from South Dakota to Illinois Mid-Year: Which State Tax Returns Do You File?
Answer
Illinois taxes the second half of the year. South Dakota has no personal income tax, so the pre-move income is untouched at state level; the Illinois part-year return picks up from the date you became a Illinois resident and prorates your deductions to that stretch.
Last verified
Coming from a state with no income tax means arriving with no Illinois withholding history and no prior-year liability to base estimates on. The first Illinois return is where that catches up, so the withholding start date matters.
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 there is nothing to file for the earlier part of the year.
The two states, side by side
| South Dakota | Illinois | |
|---|---|---|
| Taxes wages | No | Yes — flat |
| Reciprocity partners | None | 4 (Form IL-W-5-NR) |
| Convenience rule | No | No |
| Nonresident return | Not applicable | Form IL-1040 with Schedule NR |
| Part-year return | Not applicable | Form IL-1040 with Schedule NR |
| Credit for other-state tax | No income tax | Schedule CR |
| Nonresident safe harbour | Not applicable | 30 days |
| Local income tax | No | No |
| Revenue department | South Dakota 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 South Dakota gives:One part-year return — the state you left.
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: South Dakota → IllinoisWork state only
- Remote worker: South Dakota → IllinoisNo state income tax on your wages
- 1099 contractor: South Dakota → IllinoisClient state only, if you work there
Other South Dakota pairs
Questions people actually ask
I moved from South Dakota to Illinois mid-year. Do I have to file in both states?
Illinois taxes the second half of the year. South Dakota has no personal income tax, so the pre-move income is untouched at state level; the Illinois part-year return picks up from the date you became a Illinois resident and prorates your deductions to that stretch.
How do I split my income between South Dakota and Illinois?
By when you received it, measured against the date your domicile actually changed. Income received while you were a South Dakota resident belongs on the South Dakota return and income received afterwards on the Illinois return. Keep evidence of the move date — a lease, a closing statement, a licence issue date.
How current is this?
The South Dakota and Illinois rules on this page were last checked against South Dakota 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.
- South Dakota Department of Revenue — individual income taxaccessed 2026-08-07
- Illinois Department of Revenue — individual income taxaccessed 2026-08-07