State Tax Reciprocity for Locums: Why 1099 Doesn’t Count

Reciprocity is the most misunderstood word in multi-state physician taxes. A reciprocity agreement between two states says: if you live in one and earn wages in the other, only your home state taxes those wages. File one exemption certificate with the employer, and the work state disappears from your tax life. It is real, it is convenient, and for most locum physicians it is irrelevant.

The catch is in the fine print every agreement shares: reciprocity covers W-2 wages only. Locum tenens income paid on a 1099, which is how most locum work is paid, is self-employment income, and no reciprocity agreement anywhere covers it. A 1099 locum living in Pennsylvania and working in New Jersey, two states with one of the oldest reciprocity pacts in the country, still files a New Jersey nonresident return and claims a credit on the Pennsylvania return.

This guide gives you the complete 2026 reciprocity map, explains the nonresident-return-plus-credit mechanics that actually govern 1099 income, and covers the two overlays that ambush mobile physicians: convenience-of-the-employer rules and the tax home concept.

Seventeen jurisdictions maintain reciprocity agreements. The table reads: residents of the partner states who earn W-2 wages in the listed state are exempt from that state’s withholding and tax on those wages, once they file the exemption certificate with the employer.

Every reciprocity agreement is drafted around employer wages: compensation subject to withholding, paid by an employer, reported on a W-2. Independent contractor income is business income sourced to where the services are performed, and the agreements simply do not reach it. A 1099 locum owes nonresident tax in each state with an income tax where they worked, files a Schedule C sourced across those states, and claims a resident credit at home for taxes paid elsewhere.

The credit is capped at the home-state tax on that same income, which produces the higher-of-the-two-rates result. Working in a state with a higher rate than home, you pay the difference on top; working in a lower-rate state, the credit wipes out the home-state tax on those dollars but never generates a refund of the excess.

Watch the local layer: several states’ local taxes sit outside the credit system. Philadelphia’s wage tax, Ohio municipal taxes, and other city-level levies may not be creditable against another state’s tax, and credit rules for them vary by home state.

Take an Illinois-resident hospitalist with a mixed 2026: a W-2 position at an Iowa hospital across the border, a $60,000 block of 1099 locum shifts in Georgia, and a $40,000 stretch of 1099 work in Texas. Three assignment jurisdictions, three completely different treatments.

The Iowa W-2 job is the easy one, because Iowa and Illinois are reciprocal. She files Iowa’s employee exemption certificate with the hospital’s payroll office before the first paycheck, Iowa withholds nothing, Illinois withholding (or her own estimates) covers the wages at Illinois’s flat 4.95%, and at filing time Iowa simply does not appear on her return stack. Had she skipped the certificate, Iowa would have withheld all year at its 3.8% flat rate and she would file an Iowa nonresident return solely to recover money that was never owed.

The Georgia 1099 block gets the full nonresident treatment, because reciprocity never touches contractor income and Georgia has no agreements with anyone regardless. She registers for Georgia estimated payments, remits quarterly on the $60,000 as it is earned, files a Georgia nonresident return sourcing that income, and claims a credit on her Illinois return for the Georgia tax paid, capped at the Illinois tax on the same income. With Georgia’s 2026 flat rate at 4.99% and Illinois at 4.95%, the credit absorbs nearly all of the Illinois tax on those dollars and she nets out at roughly the Georgia rate, the higher of the two.

The Texas stretch generates no Texas filing at all, but no windfall either: Illinois taxes its residents’ worldwide income, so the $40,000 lands on her IL-1040 at 4.95% with no credit to claim, because no Texas tax was paid. Working in a no-tax state only helps physicians who actually live in one. Her final stack: federal return, Georgia nonresident return, Illinois resident return with the credit schedule, plus quarterly estimates to the IRS, Georgia, and Illinois through the year.

Locum staffing agencies process payroll for physicians scattered across dozens of states, and their withholding systems fail in predictable ways. The most common: withholding for the wrong state entirely, typically the agency’s home state or the state on file from your onboarding address, rather than the assignment state where the income is actually sourced. The result is a year of withholding building up credit in a state where you owe nothing, while the state you actually worked in accrues an unpaid balance with penalties.

On W-2 arrangements, the other classics: ignoring a reciprocity certificate you filed (or never offering one), continuing old-state withholding after you change assignments mid-year, and issuing a W-2 whose state boxes do not match where you physically worked, which forces you to reconstruct the allocation from your own records at filing time. On 1099 arrangements the failure is simpler and total: nothing is withheld anywhere, federal or state, and physicians coming off employed positions routinely discover this in April rather than June.

The defense is a five-minute review of the first pay stub of every assignment: confirm which state’s tax is being withheld, confirm it matches where you are working (or your home state if reciprocity applies and your certificate is on file), and confirm the year-to-date state wage figures reset correctly when assignments change. Fixing a misdirected withholding in week two is a payroll email; fixing it in February means filing an extra nonresident return to claim a refund from the wrong state while paying the right state late, often with penalties that were never necessary.

Five states apply a full convenience-of-the-employer rule in 2026: New York (the strictest), Delaware, Nebraska (where 7 or more days of physical presence triggers it, under its 2024 law), Pennsylvania, and Alabama. If your W-2 employer is based in one of these states and you work remotely from another state for your own convenience rather than the employer’s necessity, the employer’s state claims tax on those wages anyway.

Connecticut and New Jersey run retaliatory versions that apply only to residents of other convenience states, and Oregon has a narrow variant. The rule is how a telehealth physician living in Florida with a New York-based W-2 employer ends up owing New York tax on days never spent in New York, and it can also produce genuine double-tax friction when the resident state limits its credit.

Two boundaries keep it contained: it is a W-2 doctrine, so 1099 locum and telemedicine contractors are outside it (their income sources to where they physically perform the work), and employer-required work locations, a credentialed hospital shift, for instance, are necessity, not convenience.

Your tax home, in IRS terms, is your regular place of business, not your house. For locums who travel, keeping a tax home (usually where your permanent residence and recurring work base sit) is what makes travel, lodging, and per diem costs deductible business expenses on assignments away from home. Physicians who work a single assignment location so long it becomes indefinite, generally the one-year mark, can see their tax home shift to the assignment and the travel deductions evaporate.

Residency is the second layer: your domicile state taxes worldwide income, and states apply statutory-resident tests (commonly 183 days plus an abode) that can claim you as a resident even while you consider yourself a visitor. Contemporaneous day counts by state are the cheap insurance for both issues.

The rhythm that keeps a multi-state 1099 year clean: track days and income by state as you go, register and pay estimated taxes in the states that require them, file each nonresident return, then take the resident credit at home. Our locum tenens tax guide and the state-specific pages linked below cover assignment-state details, and the estimator tool models the federal side.