Blaine County, Montana property-tax payment and appeal deadlines
Tax bills, payment rules, and valuation-review windows are controlled by the local jurisdiction and the governing state framework. The reviewed record below separates published figures from items that still require confirmation with Montana Department of Revenue Property Assessment Division — Havre Field Office / Blaine County Treasurer.
Rate context
Confirmno single countywide effective rate; Montana local mill levies and special assessments vary by taxing jurisdiction. For 2026, Montana DOR homestead/long-term-rental rates are tiered at 0.76%, 0.90%, 1.10%, and 1.90% by market-value bracket.
Statement mailing
Confirmno official 2026 county-specific tax-bill mailing date was published in the sources reviewed.
Payment deadline
PublishedFor tax year 2026, Montana real-property taxes are due by 5:00 p.m. November 30, 2026 for the first payment and May 31, 2027 for the second payment; if a due date falls on a weekend or holiday, the next business day applies.
Valuation protest
PublishedFor the 2025–2026 valuation cycle, file Form AB-26 or appeal to the county Tax Appeal Board within 30 days of the Department of Revenue classification/appraisal notice; late informal review was available through June 1, 2026. A written protest must also be filed with the county treasurer and disputed taxes paid under protest by the tax due date.
Do not assume a grace period.
The reviewed record identifies the payment timing above but does not establish a universal penalty schedule for this page. Late charges, interest, collection costs, tax-sale procedures, and lien or foreclosure timelines can depend on state law and the local collector’s process. If the deadline is close or a balance is delinquent, contact the tax collector directly and request the current payoff amount in writing.
Treat a published payment deadline as a hard operational date and retain your receipt or confirmation number.
From assessment to collection
01Valuation and notice
Review the assessment notice as soon as it arrives. The protest window may run from the notice date rather than from the payment due date.
02Statement and account review
Match the tax statement to the parcel or account number and confirm exemptions, assessed value, taxing units, credits, and balance.
03Payment confirmation
Use the official collector channel, then save the receipt, transaction reference, and date posted. A bank submission is not always the same as a county posting date.