Moved from Kentucky to Idaho Mid-Year: Which State Tax Returns Do You File?
Answer
Two returns, split at the move date. Kentucky and Idaho 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 · KentuckyForm 740-NP
File a Kentucky part-year return covering the months you lived in Kentucky. A part-year resident of Kentucky reports the income received while a Kentucky resident, plus any Kentucky-source income received during the rest of the year, and prorates the deductions and credits to the residency period.
- 2Part-year return · IdahoForm 43 (part-year resident)
File a Idaho part-year return covering the months you lived in Idaho. A part-year resident of Idaho reports the income received while a Idaho resident, plus any Idaho-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
| Kentucky | Idaho | |
|---|---|---|
| Taxes wages | Yes — flat | Yes — flat |
| Reciprocity partners | 7 (Form 42A809) | None |
| Convenience rule | No | No |
| Nonresident return | Form 740-NP | Form 43 |
| Part-year return | Form 740-NP | Form 43 (part-year resident) |
| Credit for other-state tax | Schedule ITC | Form 39NR |
| Nonresident safe harbour | None published | None published |
| Local income tax | Yes | No |
| Revenue department | Kentucky Department of Revenue | Idaho State Tax Commission |
| Last verified |
The other direction
Reversing the commute does not always reverse the answer. Living in Idaho and working in Kentucky 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: Kentucky → IdahoBoth states — credit offsets the double tax
- Remote worker: Kentucky → IdahoHome state only
- 1099 contractor: Kentucky → IdahoHome state, plus the client state if you work there
Other Kentucky pairs
Questions people actually ask
I moved from Kentucky to Idaho mid-year. Do I have to file in both states?
Two returns, split at the move date. Kentucky and Idaho 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 Kentucky and Idaho?
By when you received it, measured against the date your domicile actually changed. Income received while you were a Kentucky resident belongs on the Kentucky return and income received afterwards on the Idaho 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 Kentucky and Idaho rules on this page were last checked against Kentucky Department of Revenue and Idaho State Tax Commission 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.
- Kentucky Department of Revenue — individual income taxaccessed 2026-08-07
- Idaho State Tax Commission — individual income taxaccessed 2026-08-07