Updated September 2026 · 4 min read
Key Montana Tax Deadlines
Build a filing calendar using the current Montana Department of Revenue instructions for each tax type.
Individual & pass-through dates
Check the current Form 2 instructions for the tax year you are filing. The filing date can move when it falls on a weekend or holiday, and extensions do not automatically extend payment deadlines.
If you make estimated payments or file for a pass-through entity, confirm the current due dates and required forms with the Montana Department of Revenue before setting reminders.
Payroll and withholding schedule
Montana withholding payment frequency depends on the employer's lookback period. The Department of Revenue describes accelerated, monthly, and annual schedules in its employer guide.
The annual Montana MW-3 reconciliation is separate from federal Form W-3. Use the current Montana employer guide and your TransAction Portal account to confirm the filing schedule.
Property & specialty taxes
Property and specialty tax dates differ by tax type and filing year. Check the relevant Montana agency or county notice rather than relying on a single statewide date.
Keep separate reminders for income tax, payroll withholding, property, and any industry-specific filing obligations.
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