State Income Tax for Cross-Border Workers: Canada-US

The Canada-US tax treaty coordinates federal taxation between the two countries. It does not bind US states. Each state applies its own income tax rules, and those rules can reach cross-border workers in ways the treaty does not address. A Canadian who works remotely for a New York employer, a TN visa holder who lives in one state and commutes to a client in another, and a former California resident who left for Canada all face state-level tax obligations that sit on top of the federal and Canadian calculations.

Which states tax cross-border workers?

Any state with an income tax can tax a non-resident on income sourced to that state. The most common trigger is work physically performed in the state. If you live in Canada and travel to a US office in Illinois for 30 days a year, Illinois can tax the income earned during those 30 days.

Some states are more aggressive than others:

New York applies the convenience-of-employer test. If you work remotely from Canada for a New York employer, New York may tax the income as if you worked in New York, unless the remote work was done for the employer’s necessity (not your convenience). The test is the employer’s business reason, not your preference. A Canadian employee who works from Toronto because they live in Toronto may still owe New York tax on that income.

California has some of the broadest residency rules. If you were a California resident and moved to Canada, California may treat you as a continuing resident if you maintain “closer connections” to California (property, bank accounts, professional licenses). The safe-harbor period is 18 months: if you return within 18 months, the Franchise Tax Board (FTB) may treat you as a resident for the entire absence.

No-income-tax states (Florida, Texas, Washington, Nevada, Wyoming, Alaska, South Dakota, Tennessee, New Hampshire for wage income) avoid this issue entirely. A cross-border worker based in Florida has no state income tax layer.

How does state tax interact with the treaty?

It does not. Article XXVI(6) of the treaty says the treaty does not restrict any benefit granted by a state. It does not say the treaty’s exemptions apply at the state level. The treaty’s employment-income allocation (Article XV), which limits taxation to days physically worked in the source country, binds the IRS but not a state revenue department.

This means a treaty benefit at the federal level (for example, the $10,000 teacher/researcher exemption under Article XV(2)) may not be recognized by the state. Each state decides independently whether to conform to treaty provisions, and most do not.

Do I get an FTC for state tax on my Canadian return?

The Canadian FTC (Form T2209) credits “income or profits tax paid to the government of a country other than Canada.” The CRA has historically treated US state income taxes as qualifying for the FTC, because the state is a taxing jurisdiction within the United States. However, the credit is limited to Canadian tax on the same income, and if the federal FTC already absorbs most of the Canadian tax, the state FTC may have no room.

The layering works like this:

1. Calculate Canadian tax on the US-source income.
2. Claim the FTC for US federal tax paid on that income.
3. If Canadian tax remains after the federal FTC, claim the FTC for state tax paid, up to the remaining Canadian tax.

If the US federal tax rate on the income exceeds the Canadian rate, the federal FTC eliminates the Canadian tax, and the state FTC has nothing to offset. The state tax becomes a pure additional cost with no cross-border relief.

What about provincial tax for Canadians working in the US?

Provincial tax is residency-based: you pay provincial tax in your province of residence, on your worldwide income. If you are a Canadian resident living in Ontario and earning US-source income, Ontario taxes that income, and the Canadian FTC (both federal and provincial) offsets the US tax.

If you leave Canada and become a non-resident, provincial tax stops. There is no trailing nexus equivalent for Canadian provinces. The departure is clean once the residency tie is severed.

What if I work in multiple states?

Multi-state taxation is common for consultants, project-based workers, and employees who travel. Each state can tax the portion of income earned within its borders, typically measured by days worked there divided by total working days.

Some states have reciprocity agreements with each other (for example, New Jersey and Pennsylvania), but these agreements do not extend to Canadian residents. A Canadian working in both New York and New Jersey may owe tax to both states, with credits offsetting partial overlap.

Filing requirements vary: some states require a return even for one day of work there, while others have de minimis thresholds (for example, 14 days or $600 of income). The thresholds are state-specific and change.

What about remote work from Canada for a US employer?

This is the fastest-growing cross-border state tax question. A Canadian resident who works remotely for a US employer from their home in Canada is not physically present in any US state. Most states do not tax income for work performed entirely outside the US.

The exception is New York’s convenience test. If your employer’s office is in New York and you work from Canada for your own convenience (rather than the employer’s business necessity), New York may claim the income as New York-source. The employer’s withholding decision determines the initial compliance: if the employer withholds New York tax, you must file a New York return to claim a refund if you believe the convenience test does not apply.

Other states with similar doctrines (Pennsylvania, New Jersey, Connecticut, and Nebraska have considered or adopted variations) may follow. Check the employer’s state before assuming remote work from Canada avoids US state tax entirely.

What should I do next?

Identify every state where you have income, property, or former residency. Check that state’s non-resident filing threshold and source rules. Then layer the state tax into your overall cross-border plan: the federal treaty handles the IRS and CRA coordination, but the state layer is separate.

• W-4 withholding for cross-border workers, setting up federal withholding
• Cross-border tax return cost, state returns add to the bill
• Form 1116 and the FTC, the federal FTC that absorbs before state credits apply
• Estimated tax payments, state estimated payments run parallel

This guide is general information, not tax advice for your specific situation. Which points apply, and how, depends on your facts.