Population of Counties in Iowa (2018)

Name 2018 Population Growth Rate
Polk County474,7689.84%
Linn County221,9004.84%
Scott County172,0454.11%
Johnson County146,63311.68%
Black Hawk County132,8131.27%
Woodbury County102,7070.34%
Story County96,8168.02%
Dubuque County96,7042.95%
Pottawattamie County93,5080.17%
Dallas County84,18526.14%
Warren County49,3436.48%
Clinton County47,236-3.78%
Cerro Gordo County43,064-2.33%
Muscatine County42,9040.38%
Marshall County40,160-1.30%
Des Moines County39,625-1.52%
Webster County36,752-2.99%
Jasper County36,661-0.41%
Wapello County35,270-1.11%
Sioux County34,8913.42%
Lee County34,456-3.88%
Marion County33,149-0.23%
Boone County26,4190.57%
Benton County25,641-1.57%
Plymouth County25,2050.94%
Bremer County24,7842.01%
Mahaska County22,206-0.89%
Washington County22,1091.93%
Buchanan County21,0340.27%
Winneshiek County20,409-3.16%
Jones County20,384-1.47%
Carroll County20,366-2.20%
Buena Vista County20,268-0.31%
Fayette County19,986-4.18%
Henry County19,801-1.50%
Jackson County19,390-2.18%
Cedar County18,407-0.51%
Poweshiek County18,292-3.33%
Jefferson County18,1727.98%
Clayton County17,647-2.40%
Delaware County17,269-2.75%
Hardin County17,193-2.00%
Tama County17,179-3.04%
Dickinson County17,1042.60%
Crawford County17,036-0.71%
Clay County16,325-1.85%
Iowa County16,184-0.92%
Floyd County15,835-2.95%
Madison County15,7940.39%
Page County15,335-3.65%
Kossuth County15,133-2.51%
Hamilton County15,100-3.40%
Mills County15,044-0.21%
Butler County14,687-1.55%
Harrison County14,072-5.61%
O'Brien County13,921-3.38%
Allamakee County13,869-3.51%
Cass County13,180-5.38%
Wright County12,816-2.75%
Appanoose County12,497-2.79%
Union County12,390-0.97%
Grundy County12,297-1.35%
Chickasaw County12,063-2.77%
Lyon County11,7881.90%
Shelby County11,672-4.11%
Cherokee County11,404-5.87%
Louisa County11,188-1.69%
Hancock County10,893-3.60%
Mitchell County10,657-1.21%
Guthrie County10,650-2.61%
Winnebago County10,601-2.17%
Franklin County10,200-4.69%
Keokuk County10,177-3.16%
Montgomery County10,134-5.19%
Sac County9,818-5.18%
Calhoun County9,799-3.55%
Emmet County9,558-6.91%
Humboldt County9,531-2.67%
Clarke County9,286-0.34%
Howard County9,272-3.11%
Palo Alto County9,042-3.79%
Greene County9,009-3.76%
Davis County8,9011.44%
Monona County8,799-4.86%
Lucas County8,556-3.81%
Decatur County8,045-4.44%
Monroe County7,853-1.78%
Worth County7,475-1.52%
Van Buren County7,255-4.27%
Adair County7,010-8.71%
Fremont County6,960-6.41%
Ida County6,957-1.56%
Pocahontas County6,848-6.05%
Wayne County6,4370.28%
Taylor County6,237-1.30%
Osceola County6,084-5.75%
Audubon County5,635-7.59%
Ringgold County4,989-2.44%
Adams County3,716-7.63%