Idaho — Tax Residency Rule

Summary

Day threshold

More than 270 days in Idaho

Window

Taxable year (usually 1 Jan – 31 Dec)

Also required

A place of abode in Idaho for the entire year

Part days

Count, unless the day's presence was temporary

Effect

Full-year Idaho resident, taxed on all income

Basis

Idaho Code §63-3013

If you are not domiciled in Idaho, you still become an Idaho resident for tax purposes when both are true for the taxable year: you maintain a place of abode in Idaho for the entire year and you spend more than 270 days of the year in the state. Stay at or under 270 days, or keep no Idaho home for the whole year, and you avoid this route — so day 271 is the line to watch. Residence means Idaho taxes all of your income.

Who it applies to

This matters most if you are:

• A remote worker or frequent traveler who spends long stretches of the year in Idaho.
• Someone who keeps a second home or family home in Idaho while living or working elsewhere.
• An Idaho domiciliary working abroad or out of state for an extended period.

The rule turns on physical presence and available housing, not on citizenship or visa status — although anyone who is a nonresident alien for federal purposes is, by statute, not an Idaho resident under this section. People domiciled in Idaho for the entire year are residents by domicile and never need the 270-day test.

The rule — and why it exists

Idaho Code §63-3013(1) makes you a resident if either is true:

• Domicile. You are domiciled in Idaho for the entire taxable year; or
• Abode + days. You maintain a place of abode in Idaho for the entire taxable year and spend in the aggregate more than 270 days of the taxable year in the state.

The 270-day route only bites when both parts are present, and the abode part is strict on timing: a home kept for only part of the year does not satisfy it. Someone who moves to or from Idaho mid-year is normally a part-year resident instead.

How it compares: 270 days is well above the common 183-day rule used by states such as New York and Connecticut. The other conditions are stricter, though: the abode must exist for the whole year, and part days count by statute.

Counting the days

Idaho totals your presence across the whole taxable year. In practice:

1. 1Count every day, or part of a day, that you are present in Idaho — the statute treats any part of a calendar day as a day in the state.
2. 2The exception: a day whose presence you can show was for a temporary or transitory purpose, such as passing through, does not count.
3. 3Add up the qualifying days between 1 January and 31 December — they need not be consecutive.
4. 4More than 270 days, combined with an Idaho abode maintained all year, makes you a resident; 270 or fewer does not.

Examples

Example 1 — resident by abode and days

You own a home in Boise that you keep all year, and you stay in Idaho for about 300 days while working remotely. You maintain a place of abode for the entire year and exceed 270 days, so you are an Idaho resident and Idaho taxes all your income.

Example 2 — over 270 days but no year-round home

You spend 285 days in Idaho but live entirely out of short-term rentals and never keep any one dwelling available to you for the whole year. Because you have no place of abode maintained for the entire year, the day count alone does not make you a resident under this route.

Example 3 — Idaho home but few days

You keep a furnished cabin in Idaho all year but are there only ~120 days, and Idaho is not your domicile. You fall short of 270 days, so the abode-plus-days test is not met and you are not a full-year resident on that basis — though Idaho can still tax Idaho-source income.

Exceptions & edge cases

• Domicile overrides the day count. If Idaho is your domicile, you are a resident even if you spend far fewer than 270 days there in a given year.
• The 445-day absence exception. Under §63-3013(2), an Idaho domiciliary is not a resident (though they may be a part-year resident) during a period of absence that begins when they leave Idaho, if they are absent for at least 445 days in the first 15 months after leaving. Throughout that period they must also: not be present in Idaho more than 60 days in any calendar year (days within the first 15 months are excluded from this limit); not maintain a permanent place of abode in Idaho at which their spouse (unless legally separated) or minor or dependent children are present more than 60 days in any calendar year; not hold an elective or appointive US government office (the armed forces and career US foreign service appointees excepted) or work on the staff of an elected member of the US Congress; and not claim Idaho as their tax home for federal income tax purposes. The period ends when they return and remain or reside in Idaho for more than 60 days. Under the Tax Commission's rules, the exception does not apply to an Idaho-domiciled servicemember or spouse covered by the Servicemembers Civil Relief Act.
• Part-year moves. If you establish or abandon Idaho domicile mid-year, you are generally a part-year resident, taxed on all income received while an Idaho resident plus Idaho-source income for the rest of the year.
• The abode must be genuinely available. A property you have fully let to tenants and cannot use yourself is hard to describe as your place of abode.

Common misconceptions

• "Under 270 days means I owe Idaho nothing." False — if Idaho is your domicile you are a resident with any number of days, and Idaho-source income is taxable either way.
• "More than 270 days automatically makes me a resident." False — without a place of abode in Idaho for the entire year, the day count alone does not trigger this route.
• "A few hours in Idaho don't count." They do — any part of a calendar day is a day, unless you can show that day's presence was temporary or transitory.
• "Only my Idaho income is taxed." A resident is taxed on income from all sources, the same as a domiciled resident.

Frequently asked questions

Sources

• Idaho Code §63-3013 — Resident
• Idaho State Tax Commission — Individual Income Tax Basics (residency status)
• Idaho State Tax Commission — Guidance for specific circumstances of residency
• IDAPA 35.01.01 — Income Tax Administrative Rules, Rule 030 (Resident)