Resident Population in Lyman County, SD was 3.70500 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Lyman County, SD reached a record high of 4.06000 in January of 1970 and a record low of 3.60300 in January of 1987. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Lyman County, SD - last updated from the United States Federal Reserve on May of 2024.