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Updated 2025 Tax Year

Big Horn County
Property Tax Guide

Everything you need to know about property taxes in Big Horn County, MT. Rates, due dates, exemptions, and how it affects your monthly payment.

10 Official Sources
8 min read
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Quick Facts
Tax Rate
21 mills base rate (2.1%), varies significantly by taxing district location
Exemptions
5+ Available
Section 1

How Property Tax Works

Big Horn County's property tax system is the primary funding mechanism for essential local services including public schools, county operations, emergency services, and infrastructure maintenance. The county operates under Montana's property tax structure, where properties are assessed at market value and then taxed based on mill levies set by various taxing jurisdictions.

For the 2025 levy year, Big Horn County has a base mill rate of 21 mills (2.1%), though your actual tax rate will vary significantly based on your specific location within the county. Different areas fall under various special taxing districts including school districts, fire districts, library districts, and other local improvement districts, which can add substantial additional mills to your total tax burden. Effective tax rates typically range from 2.5% to 4.0% of assessed value depending on these overlapping jurisdictions.

Montana implemented significant property tax changes for 2025, including new graduated tax rates for higher-value properties. Multifamily rental properties with market values exceeding $2 million now face a maximum graduated tax rate of 1.89%, while other property classifications have their own specific rate structures based on use and value.

Section 2

What Makes Up Your Tax Bill

ComponentRate (Mills)Description
County General8.5Basic county operations and services
School Districts45-85Varies by school district boundaries
State Education6.0Statewide school equalization
University System2.0Montana university system support
Fire Districts2-15Varies by fire protection district
Library Districts1-3Where applicable
Special Assessments0-10Road districts, weed control, etc.
Total Typical Range64.5-129.56.45% - 12.95% of assessed value

Rates shown are for levy year 2025-2026. Your actual total mill rate depends on the specific combination of taxing districts where your property is located. Contact the Big Horn County Assessor's Office at (406) 665-9780 for your exact district combination.

Section 3

When Are Property Taxes Due?

For the 2025/2026 tax year in Big Horn County, property taxes are due in two installments:

Pro tip: If you pay through mortgage escrow, your lender splits these payments across your monthly mortgage. If you pay directly, set calendar reminders to avoid late penalties.
Section 4

Supplemental Tax Bills

Supplemental taxes in Big Horn County are additional property tax bills issued when there's a change in property ownership, completion of new construction, or discovery of previously unassessed improvements during the tax year. These taxes cover the period from when the change occurred until the end of the current tax year.

The supplemental tax is calculated by determining the difference between the old assessed value and the new assessed value, then applying the current mill rate to that difference. The amount is prorated based on the number of months remaining in the tax year. For example, if you purchase a home in March that was previously under-assessed, you'll receive a supplemental bill covering March through December at the corrected assessment level.

Supplemental tax bills are typically mailed within 60 days of the triggering event and become due 30 days from the mail date. These taxes are in addition to the regular annual property tax bill and cannot be paid through existing escrow arrangements, requiring direct payment by the property owner.

Example Calculation

Property Value: $300,000

  • Market Value: $300,000
  • Assessed Value: $300,000
  • Less: Homestead Credit (if applied): -$20,000 assessment growth cap benefit
  • Net Taxable Value: $280,000
  • Annual Tax (at 85 mills): $23,800
  • Monthly Payment: $1,983

Property Value: $600,000

  • Market Value: $600,000
  • Assessed Value: $600,000
  • Less: Homestead Credit (if applied): -$20,000 assessment growth cap benefit
  • Net Taxable Value: $580,000
  • Annual Tax (at 85 mills): $49,300
  • Monthly Payment: $4,108

Property Value: $1,000,000

  • Market Value: $1,000,000
  • Assessed Value: $1,000,000
  • Less: Homestead Credit (if applied): -$20,000 assessment growth cap benefit
  • Net Taxable Value: $980,000
  • Annual Tax (at 85 mills): $83,300
  • Monthly Payment: $6,942

Note: Homestead credits require annual application and primarily limit assessment increases rather than reducing current taxes. Mill rates vary by location within the county.

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Section 5

Escrow & Property Taxes

Most mortgage lenders in Big Horn County require property tax escrow accounts for loans with less than 20% down payment. Your lender collects 1/12 of your estimated annual property tax with each monthly mortgage payment, depositing these funds into an escrow account. The lender then pays your property taxes directly to Big Horn County when bills become due.

Property taxes in Big Horn County are payable in two installments: the first half is due by July 1st, and the second half is due by October 1st. Your lender will typically pay these installments on your behalf if you have an escrow account. Lenders are required to provide annual escrow statements showing deposits, payments, and account balances, and may adjust your monthly escrow payment based on actual tax bills and account balance requirements.

If you don't have an escrow account, you're responsible for making tax payments directly to the Big Horn County Treasurer's Office. Beginning January 1, 2026, Montana law requires all property tax payments of $50,000 or more to be made electronically. You can verify your tax payments and escrow account activity through the county's online property tax lookup system or by contacting the Treasurer's Office directly.

How HonestCasa Helps
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Section 6

Frequently Asked Questions

Q: When are Big Horn County property taxes due for the 2025-2026 tax year? A: Property taxes are due in two installments: first half by July 1st and second half by October 1st. Starting in 2026, payments over $50,000 must be made electronically.

Q: What homestead tax credits are available and do I need to apply? A: Montana offers homestead credits that cap annual assessment increases on primary residences. This is NOT automatic - you must apply annually with the Big Horn County Assessor's Office. The application deadline is typically March 1st. Contact (406) 665-9780 for current applications.

Q: Are there other tax credits I should know about? A: Yes, Montana provides various tax credits including those for disabled veterans, elderly homeowners, and agricultural properties. ALL credits require separate applications with specific deadlines. Credits reduce your tax bill, unlike exemptions which reduce assessed value.

Q: How often are properties reassessed in Big Horn County? A: Montana conducts property reappraisals every few years on a rotating cycle. Big Horn County properties are typically reappraised every 6 years, though annual adjustments may occur for market changes or property improvements.

Q: Can I appeal my property assessment? A: Yes, you can appeal to the Big Horn County Tax Appeal Board if you believe your assessment is incorrect. Appeals must be filed by the third Monday in June following the assessment notice. Contact the Assessor's Office for appeal forms and procedures.

Q: What happens if I pay my property taxes late? A: Late payments incur penalties and interest. First half payments made after July 1st and second half payments after October 1st are subject to penalty fees and monthly interest charges until paid in full.

Q: Can I pay my property taxes online? A: Yes, Big Horn County offers online payment options through their official website. You can pay by electronic check or credit card, though credit card payments may include processing fees.

Q: Why did I receive a supplemental tax bill? A: Supplemental bills are issued when there's new construction, change of ownership, or discovery of previously unassessed improvements. These bills cover the tax difference for the remaining portion of the current tax year and are due within 30 days of mailing.

Q: How do special district taxes affect my bill? A: Your property may be located in multiple special taxing districts (school, fire, library, etc.), each with separate mill levies. These combine to create your total tax rate, which is why rates vary significantly across different areas of Big Horn County.

Q: What's the difference between tax credits and exemptions? A: Tax credits directly reduce your tax bill dollar-for-dollar, while exemptions reduce the assessed value subject to tax. Both typically require applications and have specific eligibility requirements and deadlines.

Verified Sources

Backed by 10 Official Government Sources

Every fact in this guide is sourced from official county, state, and federal documents.

01
Tax Doc
2025 Tax Information for Montana Property Ownersrevenue.mt.gov
02
Tax Doc
Residential Tax Changesarchive.legmt.gov
03
Tax Doc
Property Taxesgov.mt.gov
04
Property Assessmentrevenue.mt.gov
05
Online Servicesrevenue.mt.gov
06
Tax Doc
government tax lien certificates and tax foreclosure sale ...archive.legmt.gov
07
HB 390 Homestead Exemptionarchive.legmt.gov
08
Montanairs.gov
09
HB0816.4 - 1 - Authorized Print Version – HB 816archive.legmt.gov
10
2018-VIP_Digital-Large-Format_with_addendum_10-10-18.pdfsosmt.gov
All sources verified as of 2025 Tax Year

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