Resident Population in Adams County, IL was 64.44100 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Adams County, IL reached a record high of 72.70000 in January of 1973 and a record low of 64.44100 in January of 2023. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Adams County, IL - last updated from the United States Federal Reserve on May of 2024.