Resident Population in Grant County, IN was 66.45800 Thous. of Persons in January of 2024, according to the United States Federal Reserve. Historically, Resident Population in Grant County, IN reached a record high of 84.10000 in January of 1972 and a record low of 65.83600 in January of 2019. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Grant County, IN - last updated from the United States Federal Reserve on April of 2026.