Resident Population in Clay County, IA was 16.51100 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Clay County, IA reached a record high of 19.60000 in January of 1979 and a record low of 16.09400 in January of 2019. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Clay County, IA - last updated from the United States Federal Reserve on May of 2024.