State tax filing

@AJFCPATax --

Both @RobertB4444 's and @Vanessa A 's answers ARE correct.

On May 18, 2015, the U.S. Supreme Court in Comptroller of the Treasury of Maryland v. Wynne [575 U. S. __ (2015)], ruled in a 5-to-4 decision that two states cannot tax the same income.

COMPTROLLER OF TREASURY OF MD. v. WYNNE | Supreme Court | US Law | LII / Legal Information Institute...

Therefore states MUST give a credit to their residents for income tax paid to another state on income taxed by both - regardless of the quirks of "sourcing" rules.

With regard to New York's taxation of remote workers (a topic which has been addressed many, many times in this forum), I offer the following citation from New York law:

The New York adjusted gross income of a nonresident individual rendering personal services as an employee includes the compensation for personal services entering into his Federal adjusted gross income, but only if, and to the extent that, his services were rendered within New York State. Compensation for personal services rendered by a nonresident individual wholly without New York State is not included in his New York adjusted gross income, regardless of the fact that payment may be made from a point within New York State or that the employer is a resident individual, partnership or corporation.

N.Y. Comp. Codes R. & Regs. Tit. 20 § 132.4 - Business, trade, profession or occupation carried on i...

NY's "convenience" rule applies only to employees who work both within and without New York during the tax year.   It does not apply to non-resident employees who never set foot in New York during the tax year.  In fact, the New York tax memorandum describing the convenience rule says so explicitly:

"The memorandum addresses situations where a nonresident or part-year resident employee whose assigned or primary work location is in New York State performs services for an employer at that location and at a home office located outside of New York State."

https://www.tax.ny.gov/pdf/memos/income/m06_5i.pdf