You're granted an automatic extension of time for filing your Montana income tax return until October 15, 2020. You do not have to apply for a federal extension in order to receive a Montana extension.
If you're required to make an extension payment, please use the Montana Form IT , 2019 Individual Income Tax Payment Voucher.
Any extension of time to file your Montana income tax return is not an extension of time to pay your income tax liability. If you haven't paid your entire 2019 income tax liability by July 15, 2020, you aren't relieved of late payment penalties and interest on your outstanding Montana income tax liability.