Resident Population in Butler County, IA was 14.17200 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Butler County, IA reached a record high of 17.80000 in January of 1979 and a record low of 14.17200 in January of 2023. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Butler County, IA - last updated from the United States Federal Reserve on May of 2024.