Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Cable | Populated Place | 360 | Champaign | 40 10 13 N | 083 37 42 W |
| Cable Cemetery | Cemetery | 355 | Champaign | 40 10 13 N | 083 37 53 W |
| Cable Cemetery | Cemetery | 259 | Erie | 41 18 33 N | 082 26 34 W |
| Cable Park Historic District | Park | 182 | Erie | 41 26 50 N | 082 42 17 W |
| Cable Post Office | Post Office | 358 | Champaign | 40 10 15 N | 083 37 40 W |
| Cable Shores Shopping Center | Locale | 332 | Stark | 40 51 08 N | 081 27 02 W |
| Cackler Cemetery | Cemetery | 326 | Portage | 41 12 12 N | 081 22 50 W |
| Cackley Swamp | Swamp | 203 | Jackson | 38 55 24 N | 082 32 17 W |
| Cactus Lake | Lake | 228 | Hamilton | 39 16 07 N | 084 18 38 W |
| Cade Hollow | Valley | | Lawrence | 38 40 40 N | 082 37 28 W |
| Cadiz | Populated Place | 385 | Harrison | 40 16 22 N | 080 59 48 W |
| Cadiz Country Club | Locale | 349 | Harrison | 40 15 02 N | 080 59 06 W |
| Cadiz Country Club Lake | Reservoir | 323 | Harrison | 40 15 00 N | 080 59 23 W |
| Cadiz Country Club Lake Dam | Dam | 323 | Harrison | 40 15 00 N | 080 59 23 W |
| Cadiz High School | School | 371 | Harrison | 40 16 07 N | 080 59 31 W |
| Cadiz Junction | Populated Place | 339 | Harrison | 40 21 33 N | 080 55 54 W |
| Cadiz Post Office | Post Office | 384 | Harrison | 40 16 25 N | 080 59 52 W |
| Cadiz Westgate Elementary School | School | 367 | Harrison | 40 16 44 N | 081 00 15 W |
| Cadmus | Populated Place | 189 | Gallia | 38 46 01 N | 082 26 13 W |
| Cadmus Covered Bridge | Bridge | 189 | Gallia | 38 46 01 N | 082 26 14 W |
| Cadmus High School (historical) | School | 189 | Gallia | 38 45 49 N | 082 26 10 W |
| Cadmus Post Office (historical) | Post Office | 188 | Gallia | 38 46 00 N | 082 26 15 W |
| Cadot Hill | Summit | 274 | Scioto | 38 43 08 N | 082 45 21 W |
| Cadwallader Cemetery | Cemetery | 311 | Trumbull | 41 16 01 N | 080 43 10 W |
| Cady Hall | Building | 189 | Athens | 39 19 26 N | 082 05 39 W |
| Cady Run | Stream | | Washington | 39 28 59 N | 081 12 22 W |
| Caesar Creek | Stream | | Warren | 39 29 36 N | 084 06 16 W |
| Caesar Creek Cemetery | Cemetery | 311 | Greene | 39 40 50 N | 083 46 58 W |
| Caesar Creek Church | Church | 279 | Warren | 39 32 51 N | 083 59 03 W |
| Caesar Creek Dike B Dam | Dam | 268 | Warren | 39 31 30 N | 084 00 60 W |
| Caesar Creek Dike F Dam | Dam | 259 | Warren | 39 30 30 N | 084 02 60 W |
| Caesar Creek Gliderport | Airport | 284 | Warren | 39 28 36 N | 084 05 38 W |
| Caesar Creek Gorge State Natural Area | Park | 220 | Warren | 39 28 52 N | 084 05 12 W |
| Caesar Creek High School | School | 308 | Greene | 39 35 10 N | 083 51 53 W |
| Caesar Creek Lake | Reservoir | 245 | Clinton | 39 29 07 N | 084 03 55 W |
| Caesar Creek Lake | Reservoir | 301 | Warren | 39 27 30 N | 083 58 24 W |
| Caesar Creek Lake Dam | Dam | 301 | Warren | 39 27 30 N | 083 58 24 W |
| Caesar Creek Lake Dike A | Dam | 301 | Warren | 39 27 30 N | 083 58 24 W |
| Caesarea Cemetery | Cemetery | 428 | Richland | 40 42 38 N | 082 28 50 W |
| Caesarea Church | Church | 427 | Richland | 40 42 38 N | 082 28 53 W |
| Caesars Creek Cemetery | Cemetery | 278 | Warren | 39 32 51 N | 083 59 01 W |
| Cahall Ridge | Ridge | 244 | Brown | 38 48 08 N | 083 54 47 W |
| Cahall School (historical) | School | 237 | Brown | 38 48 04 N | 083 54 58 W |
| Cahill School (historical) | School | 323 | Union | 40 23 25 N | 083 28 31 W |
| Cahill School (historical) | School | 297 | Union | 40 25 54 N | 083 22 15 W |
| Cahn Grove Park | Park | 309 | Ashland | 40 52 28 N | 082 17 38 W |
| Cahoon Creek | Stream | | Cuyahoga | 41 29 24 N | 081 55 36 W |
| Cahoon Park | Park | 190 | Cuyahoga | 41 29 14 N | 081 55 44 W |
| Cain Cemetery | Cemetery | 374 | Monroe | 39 46 21 N | 080 54 17 W |
| Cain Park | Park | 280 | Cuyahoga | 41 30 24 N | 081 33 35 W |
| Caine Road Bridge | Bridge | 283 | Ashtabula | 41 45 53 N | 080 36 58 W |
| Cairl Creek | Stream | | Lucas | 41 36 25 N | 083 41 28 W |
| Cairl Ditch | Canal | 195 | Lucas | 41 35 27 N | 083 45 24 W |
| Cairo | Populated Place | 248 | Allen | 40 49 55 N | 084 05 10 W |
| Cairo | Populated Place | 349 | Stark | 40 54 16 N | 081 21 37 W |
| Cairo Post Office | Post Office | 247 | Allen | 40 49 50 N | 084 05 10 W |
| Cairo Post Office (historical) | Post Office | 348 | Stark | 40 54 15 N | 081 21 39 W |
| Cairo United Church of Christ | Church | 247 | Allen | 40 49 54 N | 084 05 18 W |
| Cairo United Methodist Church | Church | 248 | Allen | 40 49 56 N | 084 04 60 W |
| Calahan Cemetery | Cemetery | 225 | Jackson | 38 56 16 N | 082 34 46 W |
| Calais | Populated Place | 261 | Monroe | 39 51 25 N | 081 16 34 W |
| Calais Cemetery | Cemetery | 301 | Monroe | 39 50 56 N | 081 16 30 W |
| Calais Post Office (historical) | Post Office | 262 | Monroe | 39 51 25 N | 081 16 37 W |
| Calamoutier | Populated Place | 396 | Holmes | 40 39 55 N | 081 47 03 W |
| Calcutta | Populated Place | 340 | Columbiana | 40 40 24 N | 080 34 35 W |
| Calcutta Cemetery | Cemetery | 378 | Columbiana | 40 40 05 N | 080 34 32 W |
| Calcutta Elementary School | School | 337 | Columbiana | 40 40 30 N | 080 34 29 W |
| Calcutta Post Office (historical) | Post Office | 340 | Columbiana | 40 40 25 N | 080 34 34 W |
| Calcutta United Presbyterian Church | Church | 376 | Columbiana | 40 40 03 N | 080 34 31 W |
| Caldwell | Populated Place | 226 | Noble | 39 44 52 N | 081 30 59 W |
| Caldwell Cemetery | Cemetery | 267 | Highland | 39 17 45 N | 083 27 16 W |
| Caldwell Cemetery | Cemetery | 250 | Meigs | 39 09 26 N | 081 50 45 W |
| Caldwell Cemetery | Cemetery | 181 | Ross | 39 13 18 N | 082 51 02 W |
| Caldwell Elementary School | School | 228 | Noble | 39 44 51 N | 081 31 12 W |
| Caldwell Farm Cemetery | Cemetery | 211 | Pickaway | 39 45 14 N | 083 01 01 W |
| Caldwell High School | School | 230 | Noble | 39 45 02 N | 081 31 04 W |
| Caldwell Laboratory | Building | 229 | Franklin | 40 00 08 N | 083 00 55 W |
| Caldwell Lake | Reservoir | 228 | Noble | 39 46 30 N | 081 31 41 W |
| Caldwell Lake | Reservoir | 219 | Ross | 39 13 42 N | 082 57 06 W |
| Caldwell Lake Dam | Dam | 228 | Noble | 39 46 30 N | 081 31 41 W |
| Caldwell Lake Dam | Dam | 221 | Ross | 39 13 42 N | 082 57 06 W |
| Caldwell Park | Park | 169 | Hamilton | 39 12 07 N | 084 29 24 W |
| Caldwell Post Office | Post Office | 226 | Noble | 39 44 50 N | 081 30 59 W |
| Caldwell School (historical) | School | 213 | Pickaway | 39 39 52 N | 083 00 05 W |
| Caldwell Spring Lake | Reservoir | 327 | Columbiana | 40 45 36 N | 080 35 11 W |
| Caldwell Spring Lake Dam | Dam | 327 | Columbiana | 40 45 36 N | 080 35 11 W |
| Caldwell Student Center | Building | 234 | Montgomery | 39 44 16 N | 084 10 53 W |
| Caldwell United Methodist Church | Church | 227 | Noble | 39 44 48 N | 081 31 06 W |
| Caldwells Addition | Populated Place | 229 | Wood | 41 11 13 N | 083 25 28 W |
| Calebs Hill | Summit | 354 | Highland | 39 08 26 N | 083 43 07 W |
| Caledonia | Populated Place | 303 | Marion | 40 38 11 N | 082 58 09 W |
| Caledonia Cemetery | Cemetery | 301 | Marion | 40 37 58 N | 082 57 31 W |
| Caledonia Elementary School | School | 248 | Cuyahoga | 41 32 06 N | 081 33 45 W |
| Caledonia Elementary School | School | 304 | Marion | 40 38 27 N | 082 58 07 W |
| Caledonia Graveyard | Cemetery | 301 | Marion | 40 38 18 N | 082 58 01 W |
| Caledonia Memorial United Methodist Church | Church | 303 | Marion | 40 38 07 N | 082 58 10 W |
| Calers Ridge | Ridge | 207 | Sandusky | 41 24 46 N | 083 24 55 W |
| Calhoun Bridge | Bridge | 183 | Gallia | 38 58 21 N | 082 24 28 W |
| Calhoun Hall | Building | 261 | Hamilton | 39 07 43 N | 084 31 02 W |
| Calhouns Memorial Temple Church | Church | 247 | Franklin | 39 58 07 N | 082 58 10 W |
| Calico Creek | Stream | | Logan | 40 29 00 N | 083 58 03 W |
| Calico Ridge | Ridge | 315 | Hocking | 39 28 54 N | 082 24 46 W |
| California | Populated Place | 155 | Hamilton | 39 03 55 N | 084 25 24 W |
| California Avenue Wesleyan Church | Church | 182 | Hamilton | 39 10 34 N | 084 28 37 W |
| California Branch | Stream | | Hocking | 39 27 01 N | 082 43 25 W |
| California Day Camp | Locale | 175 | Hamilton | 39 04 32 N | 084 24 59 W |
| California Farm (historical) | Locale | 358 | Knox | 40 20 40 N | 082 14 03 W |
| California Golf Course | Locale | 178 | Hamilton | 39 04 01 N | 084 25 06 W |
| California Hollow | Valley | | Columbiana | 40 37 18 N | 080 35 20 W |
| California Hollow | Valley | | Ross | 39 15 18 N | 083 11 39 W |