Estimate, Median Age by Sex, Total Population (5-year estimate) in Prairie County, MT was 47.20000 Years of Age in January of 2022, according to the United States Federal Reserve. Historically, Estimate, Median Age by Sex, Total Population (5-year estimate) in Prairie County, MT reached a record high of 56.30000 in January of 2012 and a record low of 47.20000 in January of 2022. Trading Economics provides the current actual value, an historical data chart and related indicators for Estimate, Median Age by Sex, Total Population (5-year estimate) in Prairie County, MT - last updated from the United States Federal Reserve on May of 2024.