Resident Population in Dallas County, IA was 115.34300 Thous. of Persons in January of 2024, according to the United States Federal Reserve. Historically, Resident Population in Dallas County, IA reached a record high of 115.34300 in January of 2024 and a record low of 26.08500 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Dallas County, IA - last updated from the United States Federal Reserve on April of 2026.