U.S. federal and state income taxes are separate taxes imposed by different governments. The IRS administers federal income tax, while each state’s tax authority administers its own system. Filing a federal return does not complete any required state filings.
1. Separate Tax Systems and Filing Requirements
Federal income tax follows federal law. State income tax rules vary, and some states do not impose individual income tax on wages. Certain cities and other local jurisdictions also impose income taxes.
Your residence and work locations help determine which returns and payments are required.
2. Residency Rules May Differ
Federal and state tax residency are not necessarily the same. Federal nonresident status does not, by itself, determine your state status.
State rules may consider days present, domicile, housing, and the purpose and duration of your stay. Arrival, departure, and relocation years may require a part-year residency review.
Reference: New York State — Filing Requirements and Residency FAQs
3. Taxable Income, Deductions, and Rates Differ
A state may use federal return figures as a starting point while applying its own adjustments, deductions, credits, and rates. Federal and state taxable income and tax liabilities can therefore differ.
Reference: California FTB — Taxation of Nonresidents and Individuals Who Change Residency
4. More Than One State Return May Be Required
Living and working in different states or moving during the year may create filing obligations in multiple states.
Credits for taxes paid to another state and reciprocal agreements must be reviewed under the relevant states’ rules. Payroll withholding alone does not determine where you must file.
Information to Include in Your Inquiry
- States where you lived and the relevant dates
- States where you physically worked and the relevant periods
- Relocation, arrival, and departure dates
- Remote work and business travel to other states
- Whether state income taxes were withheld from your pay
- An overview of income other than salary
We review federal and state requirements separately and explain the necessary filings and the scope of our assistance.
This answer provides general information about individual income taxes. Filing requirements and tax calculations depend on the tax year, states involved, and individual circumstances.
Information reviewed: October 14, 2026
