Resident Population in McCook County, SD was 5.80900 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in McCook County, SD reached a record high of 7.60000 in January of 1971 and a record low of 5.48500 in January of 2015. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in McCook County, SD - last updated from the United States Federal Reserve on May of 2024.