The graph below ranks each Ohio County by total residents according to the 2012 census estimates.
Ohio total population by county
| County | Total Population |
| Cuyahoga |  1,266,049 |
| Franklin | 1,196,070 |
| Hamilton | 802,516 |
| Summit | 541,106 |
| Montgomery | 536,270 |
| Lucas | 437,201 |
| Stark | 375,105 |
| Butler | 370,959 |
| Lorain | 301,597 |
| Mahoning | 235,463 |
| Lake | 229,528 |
| Warren | 217,310 |
| Trumbull | 207,403 |
| Clermont | 199,109 |
| Delaware | 181,188 |
| Medina | 173,725 |
| Licking | 167,715 |
| Greene | 163,852 |
| Portage | 163,851 |
| Fairfield | 147,509 |
| Clark | 136,435 |
| Wood | 128,708 |
| Richland | 122,585 |
| Wayne | 114,910 |
| Columbiana | 106,458 |
| Allen | 105,329 |
| Miami | 103,063 |
| Ashtabula | 100,298 |
| Geauga | 93,840 |
| Tuscarawas | 92,391 |
| Muskingum | 85,934 |
| Scioto | 78,592 |
| Ross | 77,475 |
| Erie | 76,390 |
| Hancock | 75,670 |
| Belmont | 69,626 |
| Jefferson | 68,360 |
| Marion | 66,216 |
| Athens | 64,489 |
| Lawrence | 62,114 |
| Washington | 61,466 |
| Knox | 60,793 |
| Sandusky | 60,461 |
| Huron | 59,294 |
| Pickaway | 56,347 |
| Seneca | 56,033 |
| Ashland | 53,199 |
| Union | 52,786 |
| Darke | 52,501 |
| Shelby | 49,197 |
| Auglaize | 45,869 |
| Logan | 45,442 |
| Brown | 44,429 |
| Holmes | 43,094 |
| Highland | 43,047 |
| Madison | 42,982 |
| Crawford | 42,874 |
| Fulton | 42,572 |
| Clinton | 41,887 |
| Preble | 41,873 |
| Ottawa | 41,355 |
| Mercer | 40,867 |
| Guernsey | 39,835 |
| Champaign | 39,602 |
| Defiance | 38,812 |
| Williams | 37,542 |
| Coshocton | 36,840 |
| Perry | 36,000 |
| Morrow | 34,988 |
| Putnam | 34,201 |
| Jackson | 32,902 |
| Hardin | 31,654 |
| Gallia | 30,811 |
| Hocking | 29,352 |
| Fayette | 28,849 |
| Van Wert | 28,739 |
| Carroll | 28,574 |
| Pike | 28,515 |
| Adams | 28,366 |
| Henry | 28,085 |
| Meigs | 23,616 |
| Wyandot | 22,591 |
| Paulding | 19,308 |
| Harrison | 15,705 |
| Morgan | 14,926 |
| Noble | 14,601 |
| Monroe | 14,589 |
| Vinton | 13,251 |