Moved from Montana to Connecticut Mid-Year: Which State Tax Returns Do You File?
Answer
Both states want a return, but neither taxes the whole year. Moving from Montana to Connecticut splits the tax year at the date your residency changed: a Montana part-year return covers everything before it, a Connecticut part-year return everything after. Income is assigned by when it was received.
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 · MontanaForm 2 with the nonresident/part-year schedule
File a Montana part-year return covering the months you lived in Montana. A part-year resident of Montana reports the income received while a Montana resident, plus any Montana-source income received during the rest of the year, and prorates the deductions and credits to the residency period.
- 2Part-year return · ConnecticutForm CT-1040NR/PY
File a Connecticut part-year return covering the months you lived in Connecticut. A part-year resident of Connecticut reports the income received while a Connecticut resident, plus any Connecticut-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
| Montana | Connecticut | |
|---|---|---|
| Taxes wages | Yes — graduated | Yes — graduated |
| Reciprocity partners | 1 (Form MW-4) | None |
| Convenience rule | No | Only against convenience-rule states |
| Nonresident return | Form 2 with the nonresident/part-year schedule | Form CT-1040NR/PY |
| Part-year return | Form 2 with the nonresident/part-year schedule | Form CT-1040NR/PY |
| Credit for other-state tax | Form 2 (credit for income tax paid to another state) | Schedule 2 (Form CT-1040) |
| Nonresident safe harbour | None published | None published |
| Local income tax | No | No |
| Revenue department | Montana Department of Revenue | Connecticut Department of Revenue Services |
| Last verified |
The other direction
Reversing the commute does not always reverse the answer. Living in Connecticut and working in Montana 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: Montana → ConnecticutBoth states — credit offsets the double tax
- Remote worker: Montana → ConnecticutHome state only
- 1099 contractor: Montana → ConnecticutHome state, plus the client state if you work there
Other Montana pairs
Questions people actually ask
I moved from Montana to Connecticut mid-year. Do I have to file in both states?
Both states want a return, but neither taxes the whole year. Moving from Montana to Connecticut splits the tax year at the date your residency changed: a Montana part-year return covers everything before it, a Connecticut part-year return everything after. Income is assigned by when it was received.
How do I split my income between Montana and Connecticut?
By when you received it, measured against the date your domicile actually changed. Income received while you were a Montana resident belongs on the Montana return and income received afterwards on the Connecticut 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 Montana and Connecticut rules on this page were last checked against Montana Department of Revenue and Connecticut Department of Revenue Services 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.
- Montana Department of Revenue — individual income taxaccessed 2026-08-07
- Connecticut Department of Revenue Services — individual income taxaccessed 2026-08-07