In 2018, Jefferson County, MT had a population of 11.8k people with a median age of 47.9 and a median household income of $66,867. Between 2017 and 2018 the population of Jefferson County, MT grew from 11,625 to 11,778, a 1.32% increase and its median household income grew from $64,911 to $66,867, a 3.01% increase.
The 5 largest ethnic groups in Jefferson County, MT are White (Non-Hispanic) (92.8%), Two+ (Non-Hispanic) (3.37%), White (Hispanic) (1.88%), American Indian & Alaska Native (Non-Hispanic) (1.09%), and Other (Hispanic) (0.45%). 0% of the people in Jefferson County, MT speak a non-English language, and 99.7% are U.S. citizens.
In 2018, the median property value in Jefferson County, MT was $277,500, and the homeownership rate was 85%. Most people in Jefferson County, MT drove alone to work, and the average commute time was 19.2 minutes. The average car ownership in Jefferson County, MT was 3 cars per household.