The state of Iowa has a total of 99 counties. Des Moines County is the oldest (founded in 1834), while Humboldt County is the youngest (established in 1857).

Polk County is the most populous, with a population of 430,640 people. Kossuth County (2,520 km2) has the largest land area, while Dickinson County has the smallest (987 km2).

Please find a list of all Iowa counties sorted alphabetically below.

• Adait County, IA
• Adams County, IA
• Allamakee County, IA
• Appanoose County, IA
• Audubon County, IA
• Benton County, IA
• Black Hawk County, IA
• Boone County, IA
• Bremer County, IA
• Buchanan County, IA
• Buena Vista County, IA
• Butler County, IA
• Calhoun County, IA
• Carroll County, IA
• Cass County, IA
• Cedar County, IA
• Cerro Gordo County, IA
• Cherokee County, IA
• Chichasaw County, IA
• Clarke County, IA
• Clay County, IA
• Clayton County, IA
• Clinton County, IA
• Crawford County, IA
• Dallas County, IA
• Davis County, IA
• Decatur County, IA
• Delaware County, IA
• Des Moines County, IA
• Dickinson County, IA
• Dubuque County, IA
• Emmett County, IA
• Fayette County, IA
• Floyd County, IA
• Franklin County, IA
• Fremont County, IA
• Greene County, IA
• Grundy County, IA
• Guthrie County, IA
• Hamilton County, IA
• Hancock County, IA
• Hardin County, IA
• Harrison County, IA
• Henry County, IA
• Howard County, IA
• Humboldt County, IA
• Ida County, IA
• Iowa County, IA
• Jackson County, IA
• Jasper County, IA
• Jefferson County, IA
• Johnson County, IA
• Jones County, IA
• Keokuk County, IA
• Kossuth County, IA
• Lee County, IA
• Linn County, IA
• Louisa County, IA
• Lucas County, IA
• Lyon County, IA
• Madison County, IA
• Mahaska County, IA
• Marion County, IA
• Marshall County, IA
• Mills County, IA
• Mitchell County, IA
• Monona County, IA
• Monroe County, IA
• Montgomery County, IA
• Muscatine County, IA
• O’Brien County, IA
• Osceola County, IA
• Page County, IA
• Palo Alto County, IA
• Plymouth County, IA
• Pocahontas County, IA
• Polk County, IA
• Pottawattamie County, IA
• Poweshiek County, IA
• Ringgold County, IA
• Sac County, IA
• Scott County, IA
• Shelby County, IA
• Sioux County, IA
• Story County, IA
• Tama County, IA
• Taylor County, IA
• Union County, IA
• Van Buren County, IA
• Wapello County, IA
• Warren County, IA
• Washington County, IA
• Wayne County, IA
• Webster County, IA
• Wineshiek County, IA
• Winnebago County, IA
• Woodbury County, IA
• Worth County, IA
• Wright County, IA