LSA image

Washington County is one of 17 counties in Iowa to reach its peak population in 2018. According to the state’s Legislative Services Agency, population growth in Iowa has been modest but steady. The average annual percent change since 1900 is a growth of 0.3%, or about 7,785 people on average. Neighboring counties that also hit their peaks in the most recent census data include Johnson and Jefferson Counties. On the other hand, Keokuk, Iowa, and Louisa counties had their peak population marks in the year 1900, and Henry County’s peak was in 1870.