Moved from Connecticut to South Dakota Mid-Year: Which State Tax Returns Do You File?
Answer
Connecticut once, and then nothing. Because South Dakota does not tax personal income, this move takes you out of the state income tax system entirely. File the Connecticut part-year return for the pre-move income and make sure Connecticut withholding actually stopped when you left.
Last verified
The clean part of this move is that only one return follows it. The part that catches people is the withholding: Connecticut tax should stop when your residency does, and it often does not without a prompt.
What you file
- 1Part-year return · ConnecticutForm CT-1040NR/PY
File a Connecticut part-year return covering the months you lived in Connecticut. South Dakota has no wage income tax, so the move ends your state filing obligation.
The two states, side by side
| Connecticut | South Dakota | |
|---|---|---|
| Taxes wages | Yes — graduated | No |
| Reciprocity partners | None | None |
| Convenience rule | Only against convenience-rule states | No |
| Nonresident return | Form CT-1040NR/PY | Not applicable |
| Part-year return | Form CT-1040NR/PY | Not applicable |
| Credit for other-state tax | Schedule 2 (Form CT-1040) | No income tax |
| Nonresident safe harbour | None published | Not applicable |
| Local income tax | No | No |
| Revenue department | Connecticut Department of Revenue Services | 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 Connecticut 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: Connecticut → South DakotaHome state only
- Remote worker: Connecticut → South DakotaHome state only
- 1099 contractor: Connecticut → South DakotaHome state only — estimated payments
Other Connecticut pairs
Questions people actually ask
I moved from Connecticut to South Dakota mid-year. Do I have to file in both states?
Connecticut once, and then nothing. Because South Dakota does not tax personal income, this move takes you out of the state income tax system entirely. File the Connecticut part-year return for the pre-move income and make sure Connecticut withholding actually stopped when you left.
How do I split my income between Connecticut and South Dakota?
By when you received it, measured against the date your domicile actually changed. Income received while you were a Connecticut resident belongs on the Connecticut 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 Connecticut and South Dakota rules on this page were last checked against Connecticut Department of Revenue Services 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.
- Connecticut Department of Revenue Services — individual income taxaccessed 2026-08-07
- South Dakota Department of Revenue — individual income taxaccessed 2026-08-07