Resident Population in Marion County, KS was 11.69000 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Marion County, KS reached a record high of 14.20000 in January of 1975 and a record low of 11.69000 in January of 2023. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Marion County, KS - last updated from the United States Federal Reserve on May of 2024.