The Basic Rule: You Owe Where You Work
Income tax is owed to every state where you perform work, based on the income earned in that state. If you earn $100K in Ohio and $100K in Florida, you owe Ohio income tax on $100K and no state tax on the Florida income (no income tax state). You may also owe your home state tax on all income, with credits for taxes paid to other states.
The Three Tax Obligations
1. Work State Tax
Every state where you physically work gets to tax the income you earned there. File a non-resident return in each work state.
2. Home State Tax
Your state of residence (tax home) taxes your worldwide income. But you get credits for taxes paid to other states, so you're not double-taxed.
3. Federal Tax
The IRS doesn't care where you worked — they tax all your income. Multi-state filing doesn't affect your federal return.
Tax Home: The Foundation
If you don't have a tax home, nothing else matters
Without a legitimate tax home, you're classified as "itinerant" — your tax home is wherever you work. This means: no travel expense deductions, no tax-free stipends, and every state where you work is your "home" for tax purposes. Read our Locum Guide for tax home requirements.
Reciprocity Agreements
Some neighboring states have reciprocity agreements — if you live in State A and work in State B, you only pay taxes to State A (your home state). This simplifies filing and prevents double-taxation.
DC / MD / VA
Full reciprocity between all three. Live in VA, work in DC? Pay VA only.
PA / NJ
Reciprocity for wages (not 1099 income in all cases — verify with CPA).
IL / IA / KY / MI / WI
Illinois has reciprocity with all four. Live in IL, work in WI? Pay IL only.
IN / KY / MI / OH / PA / WI
Various bilateral agreements. Check specific state pairs.
MN / MI / ND / WI
Minnesota has agreements with these neighbors.
Reciprocity typically applies to W2 wages. 1099 income may be treated differently — always verify with a tax professional for your specific situation.
The Optimal Tax Home Strategy
For maximum tax efficiency, consider establishing your tax home in a no-income-tax state. This means:
Establish residency in a no-income-tax state
TX, FL, TN, WA, NV are popular. Get a driver's license, voter registration, and maintain a residence there year-round.
Maintain your tax home
Pay rent/mortgage, keep belongings there, return between assignments. The IRS will audit this — have documentation.
Work assignments in income-tax states
You'll owe taxes to work states (unavoidable), but your home state won't tax you. Your stipends remain tax-free.
File non-resident returns in work states
Apportion income based on days worked in each state. Take credits on your home state return (which is zero in a no-tax state).
Use a CPA who specializes in traveling healthcare
This is not DIY territory. Multi-state filing with locum income, stipends, and S-Corp complexity requires a specialist. Budget $2-5K for tax prep.
Common Multi-State Tax Mistakes
Not filing non-resident returns
Every state where you worked expects a tax return. Not filing doesn't mean they don't know — they get W2/1099 copies. Penalties and interest accumulate quietly.
Claiming tax-free stipends without a tax home
If you're itinerant, stipends are taxable income. Getting caught means back taxes + penalties + interest on every dollar of stipend you received. This can be $50K+ in a single year.
Ignoring estimated tax payments to work states
Some states require quarterly estimated payments for non-residents. Missing these results in underpayment penalties, even if you settle up at tax time.
Not tracking days worked per state
State income apportionment is based on work days. Keep a detailed calendar: which state you worked in on every single day. An app like TripLog or a simple spreadsheet works.
Using a general-purpose CPA
Multi-state locum tax is a specialty. A CPA unfamiliar with traveling healthcare workers will miss deductions, miscalculate apportionments, and potentially cost you thousands.