Montana income tax must be filed by individuals under 65 years of age if their income is $4,790 ($9,580) or more if single/married filing separately (head of household/married filing jointly). Individuals are subject to Montana income tax if they are residents, part-year residents, or nonresidents with income sourced in the state.
Individuals who maintain domicile in the state of Montana are considered Montana residents.
Individuals who held residency in Montana at the start of the year and changed residency elsewhere or established residency in Montana during the year are considered part-year residents of the state. Part-year residents must file income tax in accordance with the nonresident/part-year resident schedule.
Nonresidents are any individuals who held no residency within the state of Montana during the tax year.