State tax filing

As a resident of New York, you must report and pay New York State income tax on all your earnings, no matter where it is earned. The general rule for New York is that until you are a resident until you can demonstrate that you have abandoned your New York domicile and established a new domicile outside New York State. 

In addition, you will have to file a non-resident Massachusetts return. You would have to apply an allocation for your total wages based on the amount of time you actually performed services in the state of Massachusetts. You will be asked to enter this amount in the screens of your Massachusetts return. 

Per the Maryland Tax Alert, Maryland imposes income tax for non-residents receiving Maryland-sourced income. Income is deemed Maryland- sourced income when the income is compensation for services performed in Maryland. 

New Hampshire does not impose state income tax so you would not be required to file a non-resident return or allocate any wages based on the amount of time you actually performed services in the state of New Hampshire. 

On your New York resident return, you will receive a resident credit for the income sourced and taxed to Massachusetts. 

The first thing you want to do is make sure you've filled out the Personal Info section correctly:

1. With your return open, select My Info in the left-hand menu.
2. Then, on the Personal info summary screen, scroll down to Other State Income, and select Edit.
3. At the Did you make money in any other states? question, answer Yes and make sure your nonresident state is selected from the drop-down.
4. Select Continue to return to your Personal info summary.
5. Click on State on the left-hand side.
6. Add Massachusetts. 
7. Follow the on-screen instructions.
8. Once you complete your MA return, the resident credit should flow to your NY return. 

To ensure accurate calculations, always complete the non-resident (MA) return first if filing in multiple states.