Resident Population in Alexander County, IL was 4.69500 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Alexander County, IL reached a record high of 12.70000 in January of 1976 and a record low of 4.69500 in January of 2023. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Alexander County, IL - last updated from the United States Federal Reserve on May of 2024.