De Amerikaanse staat Ohio is onderverdeeld in 88 county's:
thumb|right|400px|County's van Ohio
CountyInwonersU.S. Census Bureau: Annual Estimates of the Population for Counties: April 1, 2000 to July 1, 20071 juli 2007HoofdplaatsInwonersU.S. Census Bureau: Population Estimates for All Places: 2000 to 20071 juli 2007Adams28.160West Union3081Allen105.233Lima37.936Ashland54.902Ashland21.829Ashtabulla101.141Jefferson3437Athens63.275Athens21.909Auglaize46.429Wapakoneta9432Belmont67.908St. Clairsville5063Brown43.956Georgetown3506Butler357.888Hamilton62.285Carroll28.516Carrollton3208Champaign39.522Urbana11.408Clark140.477Springfield62.417Clermont193.490Batavia1690Clinton43.071Wilmington12.499Columbiana108.698Lisbon3011Coshocton36.341Coshocton11.457Crawford44.227Bucyrus12.328Cuyahoga1.295.958Cleveland438.042Darke52.205Greenville12.845Defiance38.543Defiance15.998Delaware160.865Delaware32.986Erie77.323Sandusky25.861Fairfield141.318Lancaster36.950Fayette28.308Washington Court House-Franklin1.118.107Columbus747.755Fulton42.562Wauseon7278Gallia30.841Gallipolis4174Geauga95.029Chardon5236Greene154.656Xenia23.656Guernsey40.409Cambridge11.280Hamilton842.369Cincinnati332.458Hancock74.204Findlay37.492Hardin31.650Kenton8050Harrison15.506Cadiz3308Henry28.931Napoleon8888Highland42.653Hillsboro6671Hocking28.959Logan7417Holmes41.369Millersburg3588Huron59.801Norwalk16.596Jackson33.314Jackson6168Jefferson68.730Steubenville18.864Knox58.961Mount Vernon15.950Lake233.392Painesville18.109Lawrence62.609Ironton11.320Licking156.985Newark47.176Logan46.279Bellefontaine12.737Lorain302.260Elyria55.059Lucas441.910Toledo295.029Madison41.499London9545Mahoning240.420Youngstown73.818Marion65.248Marion35.686Medina169.832Medina26.206Meigs22.895Pomeroy1968Mercer40.888Celina10.255Miami101.038Troy22.011Monroe14.258Woodsfield2429Montgomery538.104Dayton155.461Morgan14.613McConnelsville1706Morrow34.520Mount Gilead3531Muskingum85.333Zanesville25.116Noble14.096Caldwell1990Ottawa41.084Port Clinton6198Paulding19.182Paulding3367Perry34.839New Lexington4538Pickaway53.809Circleville13.648Pike27.918Waverly City4397Portage155.869Ravenna11.422Preble41.739Eaton8042Putnam34.635Ottawa4428Richland125.679Mansfield49.675Ross75.398Chillicothe22.187Sandusky60.997Fremont16.779Scioto75.958Portsmouth20.133Seneca56.705Tiffin17.363Shelby48.834Sidney20.019Stark378.664Canton78.319Summit543.487Akron207.934Trumbull213.475Warren44.270Tuscarawas91.398New Philadelphia17.339Union47.234Marysville17.622Van Wert28.889Van Wert10.269Vinton13.372McArthur2034Warren204.390Lebanon20.416Washington61.576Marietta14.153Wayne113.554Wooster26.010Williams38.378Bryan8299Wood125.399Bowling Green29.884Wyandot22.471Upper Sandusky6418
Ohio