Moved from Connecticut to Montana Mid-Year: Which State Tax Returns Do You File?
Answer
Two returns, split at the move date. Connecticut and Montana both tax residents, so each takes the portion of the year you were one. This is a residency question rather than a sourcing question — reciprocity agreements and convenience rules have nothing to do with it.
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 · 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.
- 2Part-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.
The two states, side by side
| Connecticut | Montana | |
|---|---|---|
| Taxes wages | Yes — graduated | Yes — graduated |
| Reciprocity partners | None | 1 (Form MW-4) |
| Convenience rule | Only against convenience-rule states | No |
| Nonresident return | Form CT-1040NR/PY | Form 2 with the nonresident/part-year schedule |
| Part-year return | Form CT-1040NR/PY | Form 2 with the nonresident/part-year schedule |
| Credit for other-state tax | Schedule 2 (Form CT-1040) | Form 2 (credit for income tax paid to another state) |
| Nonresident safe harbour | None published | None published |
| Local income tax | No | No |
| Revenue department | Connecticut Department of Revenue Services | Montana Department of Revenue |
| Last verified |
The other direction
Reversing the commute does not always reverse the answer. Living in Montana and working in Connecticut 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: Connecticut → MontanaBoth states — credit offsets the double tax
- Remote worker: Connecticut → MontanaHome state only
- 1099 contractor: Connecticut → MontanaHome state, plus the client state if you work there
Other Connecticut pairs
Questions people actually ask
I moved from Connecticut to Montana mid-year. Do I have to file in both states?
Two returns, split at the move date. Connecticut and Montana both tax residents, so each takes the portion of the year you were one. This is a residency question rather than a sourcing question — reciprocity agreements and convenience rules have nothing to do with it.
How do I split my income between Connecticut and Montana?
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 Montana 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 Connecticut and Montana rules on this page were last checked against Connecticut Department of Revenue Services and Montana 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
- Montana Department of Revenue — individual income taxaccessed 2026-08-07