Resident Population in Osage County, MO was 13.46800 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Osage County, MO reached a record high of 13.90900 in January of 2011 and a record low of 10.99400 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Osage County, MO - last updated from the United States Federal Reserve on May of 2024.