Does Montana tax all of your income, not just that generated there? TurboTax indicates it does.

[IreneS]

Are you filing as a full-year resident, part-year resident or nonresident?

[darel-tracy]

part-year

[IreneS]

No -- For part-year residents, Montana taxes only Montana source income: 

If you are a part-year resident, your Montana source income includes all the income your received during the part of the year you were a Montana resident, no matter where you earned it. 

Montana Income Tax Instructions 2018

To allocate your Montana source income, please follow these steps:

1. Go back into your Montana return.
2. As you go through the Montana interview, you will reach the screen Montana Taxable Income.  This starts the section  that will help you separate your Montana related income from your total income reported on your federal return.
3. On the next several screens, Montana Portion of Income, the Federal amount of income from different sources will be listed.  Enter the Montana portion in the boxes provided.
4. Continue through the screens, entering the requested information.
5. MT tax will be calculated on the MT source income you entered.  You will see a breakdown on the screen, Your Montana Tax Return Summary.