Estimate, Median Age by Sex, Total Population (5-year estimate) in Grundy County, IA was 41.60000 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 Grundy County, IA reached a record high of 42.80000 in January of 2009 and a record low of 41.60000 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 Grundy County, IA - last updated from the United States Federal Reserve on May of 2024.