In 2021, Petroleum County, MT had a population of 434 people with a median age of 50 and a median household income of $54,375. Between 2020 and 2021 the population of Petroleum County, MT declined from 464 to 434, a −6.47% decrease and its median household income grew from $40,000 to $54,375, a 35.9% increase.
The 5 largest ethnic groups in Petroleum County, MT are White (Non-Hispanic) (94%), Asian (Non-Hispanic) (5.99%), White (Hispanic) (0%), Black or African American (Non-Hispanic) (0%), and Black or African American (Hispanic) (0%).
None of the households in Petroleum County, MT reported speaking a non-English language at home as their primary shared language. This does not consider the potential multi-lingual nature of households, but only the primary self-reported language spoken by all members of the household.
100% of the residents in Petroleum County, MT are U.S. citizens.
In 2021, the median property value in Petroleum County, MT was $119,000, and the homeownership rate was 76.4%.
Most people in Petroleum County, MT drove alone to work, and the average commute time was 15.6 minutes. The average car ownership in Petroleum County, MT was 2 cars per household.
Petroleum County, MT borders Fergus County, MT, Garfield County, MT, Musselshell County, MT, Phillips County, MT, and Rosebud County, MT.