Estimate, Median Age by Sex, Total Population (5-year estimate) in Fergus County, MT was 46.70000 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 Fergus County, MT reached a record high of 48.40000 in January of 2013 and a record low of 45.00000 in January of 2020. 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 Fergus County, MT - last updated from the United States Federal Reserve on May of 2024.