Resident Population in Mississippi County, MO was 11.75000 Thous. of Persons in January of 2024, according to the United States Federal Reserve. Historically, Resident Population in Mississippi County, MO reached a record high of 17.00000 in January of 1971 and a record low of 11.68300 in January of 2022. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Mississippi County, MO - last updated from the United States Federal Reserve on April of 2026.