The State of Montana will automatically grant you a 5-month tax extension if you were approved for a federal tax extension and have paid 90% of your 2010 Montana income tax liability (or 100% of your 2009 Montana income tax liability) through your estimated tax payments or your withholding tax, or a combination of both your estimated and withholding tax payments.

However, if you need to make a state tax payment, you will need to submit Montana Form EXT-10 (PDF).

If you do not need to make a tax payment and have received an approval notification from FileLater, there’s nothing more to do. Be sure to include a copy of your federal extension (IRS Tax Form 7004 ) when you file your state tax return.

For additional information, please visit the State of Montana Department of Revenue website.

Print and Mail:
Montana State Tax Extension Form EXT-10 (PDF)

Mail with payment to:
Department of Revenue
PO Box 6309
Helena, MT 59604-6309