Resident Population in Clark County, SD was 3.94800 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Clark County, SD reached a record high of 5.70000 in January of 1972 and a record low of 3.42100 in January of 2009. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Clark County, SD - last updated from the United States Federal Reserve on May of 2024.