The graph below ranks each Ohio County by total residents according to the 2006 census estimates.
Ohio total population by county
| County | Total Population |
| Cuyahoga |  1,314,241 |
| Franklin | 1,095,662 |
| Hamilton | 822,596 |
| Summit | 545,931 |
| Montgomery | 542,237 |
| Lucas | 445,281 |
| Stark | 380,575 |
| Butler | 354,992 |
| Lorain | 301,993 |
| Mahoning | 251,026 |
| Lake | 232,892 |
| Trumbull | 217,362 |
| Warren | 201,871 |
| Clermont | 192,706 |
| Medina | 169,353 |
| Delaware | 156,697 |
| Licking | 156,287 |
| Portage | 155,012 |
| Greene | 152,298 |
| Clark | 141,872 |
| Fairfield | 140,591 |
| Richland | 127,010 |
| Wood | 124,183 |
| Wayne | 113,950 |
| Columbiana | 110,542 |
| Allen | 105,788 |
| Ashtabula | 102,703 |
| Miami | 101,914 |
| Geauga | 95,676 |
| Tuscarawas | 91,766 |
| Muskingum | 86,125 |
| Erie | 78,116 |
| Scioto | 76,441 |
| Ross | 75,556 |
| Hancock | 73,824 |
| Jefferson | 70,125 |
| Belmont | 68,771 |
| Marion | 65,583 |
| Lawrence | 63,179 |
| Washington | 61,867 |
| Athens | 61,860 |
| Sandusky | 61,625 |
| Huron | 60,313 |
| Knox | 58,561 |
| Seneca | 57,255 |
| Ashland | 54,727 |
| Pickaway | 53,606 |
| Darke | 52,780 |
| Shelby | 48,884 |
| Auglaize | 47,060 |
| Union | 46,702 |
| Logan | 46,189 |
| Crawford | 45,047 |
| Brown | 44,423 |
| Clinton | 43,399 |
| Fulton | 42,900 |
| Highland | 42,833 |
| Preble | 42,491 |
| Holmes | 41,574 |
| Madison | 41,496 |
| Ottawa | 41,331 |
| Mercer | 41,303 |
| Guernsey | 40,876 |
| Champaign | 39,921 |
| Defiance | 39,091 |
| Williams | 38,719 |
| Coshocton | 36,976 |
| Perry | 35,313 |
| Putnam | 34,744 |
| Morrow | 34,529 |
| Jackson | 33,543 |
| Hardin | 31,966 |
| Gallia | 31,313 |
| Henry | 29,520 |
| Van Wert | 29,303 |
| Carroll | 29,189 |
| Hocking | 28,973 |
| Adams | 28,516 |
| Fayette | 28,305 |
| Pike | 28,269 |
| Meigs | 23,092 |
| Wyandot | 22,553 |
| Paulding | 19,432 |
| Harrison | 15,799 |
| Morgan | 14,821 |
| Monroe | 14,606 |
| Noble | 14,165 |
| Vinton | 13,519 |