Resident Population in Brown County, IL was 6.29400 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Brown County, IL reached a record high of 6.97300 in January of 2000 and a record low of 5.40000 in January of 1978. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Brown County, IL - last updated from the United States Federal Reserve on May of 2024.