Estimate, Median Age by Sex, Total Population (5-year estimate) in Grant County, WI was 36.90000 Years of Age in January of 2023, according to the United States Federal Reserve. Historically, Estimate, Median Age by Sex, Total Population (5-year estimate) in Grant County, WI reached a record high of 38.00000 in January of 2009 and a record low of 35.60000 in January of 2017. 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 Grant County, WI - last updated from the United States Federal Reserve on September of 2025.