2026 fiscal calendar
Know the tax date before it becomes a penalty date.
Tax bills, payment rules, and valuation-review windows are controlled by the local jurisdiction and the governing state framework. The verified record below separates published figures from dates that require confirmation with Lake County Treasurer / Montana Department of Revenue Polson Field Office.
Effective rate
no single countywide effective rate was published; Montana county, municipal, school, and special-district mill levies vary by taxing jurisdiction. For 2026, Montana DOR homestead and long-term-rental rates are tiered by market-value bracket.
Statement mailing
official Lake County sources reviewed do not publish a specific 2026 real-property bill-mailing date.
Payment deadline
Tax year 2026 Montana real-property taxes: first payment due by 5:00 p.m. November 30, 2026; second payment due by 5:00 p.m. May 31, 2027. If a due date falls on a weekend or holiday, the next business day applies; the tax notice/postmark rules published by the county also apply.
Valuation protest
For the 2025–2026 valuation cycle, submit Montana DOR Form AB-26 within 30 days of the classification and appraisal notice, or file directly with the county Tax Appeal Board within 30 days. The 2026 fallback informal-review deadline was June 1, 2026.
Critical payment warning
Do not assume a grace period.
The verified county 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 the published payment deadline as a hard operational date and retain your receipt or confirmation number.
Read the calendar in order
From assessment to collection
1. Valuation 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.
2. Statement and account review
Match the tax statement to the parcel or account number and confirm exemptions, assessed value, taxing units, credits, and balance.
3. Payment 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.