Population throughout Marion County and many of the surrounding counties has remained steady according to the latest data released by the Iowa Legislative Services Agency.
From 2010-2015, based on U.S. Census Bureau estimates, the number of citizens grew by 0.2%. The latest estimate shows 33,294 people in Marion County. No population growth was reported during that six-year timeframe for Jasper County, and slight drops of less than 0.3% were reported in Mahaska and Monroe Counties.
Outside of the Des Moines metro, the fastest growing county in the area was Warren, which had a 4.9% increase, and the largest decline was in Lucas County, which had a 2.4% decrease.