I moved from VA to MT in 2023. I enter my income for MT only, but TurboTax ignores this and uses the information from my Federal return instead.

[TomK2023]

Yes, that is correct.  When you enter your income information for your federal tax return, the correct amounts will carry forward to you VA and MT part-year resident tax returns appropriately,  

[elenacarroll]

My Federal income is x. My VA income is y and my MT income is z, where y+z=x. On my VA tax I enter y, and it shows up as y on my VA return. On my MT tax I enter z, but the MT return shows x and I can't change it. This would mean in MT I had to pay tax on x when I only earned z.

[DavidD66]

Montana, like a lot of states, starts with income reported on your federal tax return and Montana tax is calculated on that income on Montana Form 2.  Your Montana income and the percentage of the tax shown on Form 2 is then determined on Schedule IV – Nonresident/Part-Year Resident Tax.  So the income you are seeing is the Form 2 income which is prior to the calculations to determine your Montana tax.  Using your example, you are paying a percentage of the Montana tax that would be owed on income of X.  That percentage is Z/X.     

[elenacarroll]

I found my error. In the confusion of moving I set the withholding amount far too low, so I owe taxes to MT