In 2020, Petroleum County, MT had a population of 464 people with a median age of 49.6 and a median household income of $40,000. Between 2019 and 2020 the population of Petroleum County, MT grew from 453 to 464, a 2.43% increase and its median household income declined from $51,250 to $40,000, a −22% decrease.
The 5 largest ethnic groups in Petroleum County, MT are White (Non-Hispanic) (96.8%), Asian (Non-Hispanic) (3.23%), 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 2020, the median property value in Petroleum County, MT was $155,700, and the homeownership rate was 65.6%.
Most people in Petroleum County, MT drove alone to work, and the average commute time was 13.3 minutes. The average car ownership in Petroleum County, MT was 2 cars per household.