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Moved from Massachusetts to Illinois Mid-Year: Which State Tax Returns Do You File?

Two part-year returnsBoth states claim the income

Answer

You file two part-year returns. Massachusetts taxes the income you received while you lived there, Illinois taxes the income you received after the move, and each state prorates your deductions and credits to its own slice of the year. The date you changed domicile is the dividing line.

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

  1. 1Part-year return · MassachusettsForm 1-NR/PY

    File a Massachusetts part-year return covering the months you lived in Massachusetts. A part-year resident of Massachusetts reports the income received while a Massachusetts resident, plus any Massachusetts-source income received during the rest of the year, and prorates the deductions and credits to the residency period.

  2. 2Part-year return · IllinoisForm IL-1040 with Schedule NR

    File a Illinois part-year return covering the months you lived in Illinois. A part-year resident of Illinois reports the income received while a Illinois resident, plus any Illinois-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

 MassachusettsIllinois
Taxes wagesYes — flatYes — flat
Reciprocity partnersNone4 (Form IL-W-5-NR)
Convenience ruleNoNo
Nonresident returnForm 1-NR/PYForm IL-1040 with Schedule NR
Part-year returnForm 1-NR/PYForm IL-1040 with Schedule NR
Credit for other-state taxSchedule OJCSchedule CR
Nonresident safe harbourNone published30 days
Local income taxNoNo
Revenue departmentMassachusetts Department of RevenueIllinois Department of Revenue
Last verified

The other direction

Reversing the commute does not always reverse the answer. Living in Illinois and working in Massachusetts gives:Two part-year returns.

Illinois to Massachusetts →

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.

Other Massachusetts pairs

Questions people actually ask

I moved from Massachusetts to Illinois mid-year. Do I have to file in both states?

You file two part-year returns. Massachusetts taxes the income you received while you lived there, Illinois taxes the income you received after the move, and each state prorates your deductions and credits to its own slice of the year. The date you changed domicile is the dividing line.

How do I split my income between Massachusetts and Illinois?

By when you received it, measured against the date your domicile actually changed. Income received while you were a Massachusetts resident belongs on the Massachusetts return and income received afterwards on the Illinois 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 Massachusetts and Illinois rules on this page were last checked against Massachusetts 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.