Petroleum County, MT Property Tax: $1,261/yr (2026)
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The effective property tax rate in Petroleum County is 0.73% of assessed home value. On a home at the county median value of $173,700, that works out to about $1,268 per year, or $106 per month. Petroleum County is located in central Montana, with Winnett as its county seat, and is home to approximately 401 residents.
About Petroleum County
Petroleum County covers approximately 1,655.6 square miles in Montana. The county is home to about 401 residents living in roughly 295 housing units, of which 52.2% are owner-occupied. The median household income is $59,318, and the median home was built in 1978.
The county seat is Winnett. Petroleum County borders Fergus County, Garfield County, Musselshell County, Phillips County, Rosebud County — useful comparisons if you're considering nearby areas with potentially different tax rates.
How Property Taxes Work in Montana
Property taxes in Montana are administered at the county level. Each county sets a millage rate applied to the assessed value of real property — the effective rate above accounts for any partial assessments and exemptions already built into the local tax base. Assessed value can differ meaningfully from current market value depending on how often the county reassesses and what fraction of market value it uses.
Most counties in Montana offer exemptions that reduce the taxable assessed value: homestead exemptions for primary residences, senior exemptions, disability exemptions, and veteran exemptions are common. These reduce your effective rate below the county-wide average shown here. Contact the Petroleum County Assessor's office to learn which exemptions apply to your property and when to file.
Petroleum County vs. Neighboring Counties
| Location | Eff. Rate | Median Home | Annual Tax |
|---|---|---|---|
| Petroleum County, MT | 0.73% | $173,700 | $1,268 |
| Montana state average | 0.77% | — | $1,337* |
| Fergus County | 0.84% | $202,700 | $1,709 |
| Garfield County | 0.66% | $178,300 | $1,169 |
| Musselshell County | 0.63% | $221,200 | $1,383 |
| Phillips County | 0.85% | $175,000 | $1,484 |
| Rosebud County | 0.63% | $188,900 | $1,191 |
| US national average | 1.10% | $281,900 | $3,101 |
*State average annual tax computed at Petroleum County's median home value of $173,700. Source: US Census ACS 2023 5-year estimates.
Frequently Asked Questions
How does Petroleum County's property tax rate compare to the rest of Montana?
At 0.73%, Petroleum County is lower than the Montana state average of 0.77%. On a home at the county median of $173,700, that means about $1,268 per year — versus $1,337 at the state average rate, a difference of $69 per year. Compared to the national average of 1.10%, Petroleum County is below average.
What's a typical annual property tax bill in Petroleum County?
For a home at the county median value of $173,700, the annual property tax in Petroleum County is approximately $1,268 — or about $106 per month. For a home worth $260,550, expect around $1,902 per year. For a $347,400 home, approximately $2,536 per year. Use the calculator above to estimate taxes for any assessed value.
Where do I appeal a Petroleum County property tax assessment?
Property assessment appeals in Petroleum County are handled by the Petroleum County Assessor's office in Winnett. Most jurisdictions require filing within 30–90 days of receiving your assessment notice — confirm the specific deadline with the assessor's office before submitting, as deadlines and procedures vary by county. A successful appeal can reduce your assessed value and lower your tax bill for the current and future tax years.
What exemptions are available in Petroleum County?
Montana counties commonly offer homestead exemptions for owner-occupied primary residences, senior citizen exemptions for qualifying homeowners aged 65 and older, exemptions for disabled residents, and veterans' exemptions. Each exemption reduces your assessed taxable value, which in turn reduces your effective tax rate below the county-wide 0.73% shown here. Contact the Petroleum County Assessor's office to confirm which exemptions are available and the application deadlines.
Data sources: US Census Bureau ACS 2023 5-Year Estimates, US Census Gazetteer (2024), County Adjacency File