Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Twin Lake Reservoir | Reservoir | 262 | Allen | 40 44 40 N | 084 05 07 W |
| Twin Lakes | Lake | 319 | Portage | 41 11 45 N | 081 20 18 W |
| Twin Lakes | Populated Place | 324 | Portage | 41 12 06 N | 081 20 26 W |
| Twin Lakes | Reservoir | 345 | Logan | 40 19 16 N | 083 47 33 W |
| Twin Lakes | Reservoir | 292 | Union | 40 17 12 N | 083 18 01 W |
| Twin Lakes (historical) | Populated Place | 277 | Miami | 40 07 19 N | 084 13 05 W |
| Twin Lakes Golf Course | Locale | 234 | Sandusky | 41 15 53 N | 082 51 08 W |
| Twin Maples Sanitarium | Hospital | 311 | Stark | 40 47 55 N | 081 30 51 W |
| Twin Maples Trailer Court | Populated Place | 206 | Wood | 41 20 31 N | 083 25 27 W |
| Twin Mobile Home Park (subdivision) | Populated Place | 321 | Ashland | 40 52 53 N | 082 18 57 W |
| Twin Oaks Golf Course | Locale | 289 | Delaware | 40 09 57 N | 083 10 04 W |
| Twin Oaks Trailer Park | Populated Place | 332 | Columbiana | 40 39 38 N | 080 37 43 W |
| Twin Pines Apostolic Church | Church | 362 | Columbiana | 40 54 04 N | 080 52 11 W |
| Twin Run | Stream | | Brown | 39 00 11 N | 083 48 18 W |
| Twin Run Golf Course | Locale | 226 | Butler | 39 27 10 N | 084 35 50 W |
| Twin Sister Knobs | Summit | 338 | Guernsey | 40 06 48 N | 081 41 03 W |
| Twin Towers County Park | Park | 311 | Greene | 39 49 06 N | 083 56 41 W |
| Twin Towers Horse Park | Park | 272 | Greene | 39 47 12 N | 084 00 35 W |
| Twin Township Cemetery | Cemetery | 207 | Ross | 39 17 14 N | 083 08 58 W |
| Twin Valley | Populated Place | 199 | Scioto | 38 47 25 N | 082 57 09 W |
| Twin Valley Baptist Church | Church | 203 | Scioto | 38 47 27 N | 082 57 08 W |
| Twin Valley Cemetery | Cemetery | 258 | Preble | 39 39 32 N | 084 29 55 W |
| Twin Valley North High School | School | 300 | Preble | 39 50 57 N | 084 32 18 W |
| Twin Valley South High School | School | 270 | Preble | 39 44 50 N | 084 31 49 W |
| Twin Willows Lake | Reservoir | 338 | Darke | 40 19 07 N | 084 46 33 W |
| Twinbrook Hills Baptist Church | Church | 238 | Butler | 39 24 28 N | 084 36 03 W |
| Twinbrook Plaza Shopping Center | Locale | 248 | Butler | 39 24 25 N | 084 36 39 W |
| Twinsburg | Populated Place | 305 | Summit | 41 18 45 N | 081 26 24 W |
| Twinsburg Centralized High School (historical) | School | 303 | Summit | 41 18 38 N | 081 26 20 W |
| Twinsburg Community Center | Building | 348 | Summit | 41 18 32 N | 081 27 44 W |
| Twinsburg Congregational Church | Church | 304 | Summit | 41 18 43 N | 081 26 32 W |
| Twinsburg Elementary School | School | 303 | Summit | 41 18 38 N | 081 26 20 W |
| Twinsburg Post Office | Post Office | 300 | Summit | 41 18 32 N | 081 26 24 W |
| Twinsburg Post Office | Post Office | 352 | Summit | 41 18 45 N | 081 16 27 W |
| Twinsburg Public Library | Building | 305 | Summit | 41 18 46 N | 081 26 27 W |
| Twinsburg Town Hall | Building | 305 | Summit | 41 18 48 N | 081 26 29 W |
| Twist Run | Stream | | Greene | 39 39 51 N | 083 56 39 W |
| Two Mile Christian Church (historical) | Church | 270 | Auglaize | 40 37 19 N | 084 11 04 W |
| Two Mile Dam | Dam | 172 | Butler | 39 24 48 N | 084 33 18 W |
| Two Mile Reservoir | Reservoir | 172 | Butler | 39 24 48 N | 084 33 18 W |
| Two Ridges Cemetery | Cemetery | 361 | Jefferson | 40 23 40 N | 080 43 57 W |
| Two Ridges Church | Church | 382 | Jefferson | 40 23 40 N | 080 43 47 W |
| Twomile Creek | Stream | | Auglaize | 40 39 40 N | 084 15 37 W |
| Twomile Creek | Stream | | Butler | 39 24 48 N | 084 33 26 W |
| Twomile Creek | Stream | | Lawrence | 38 30 42 N | 082 18 17 W |
| Twomile Creek | Stream | | Mercer | 40 24 56 N | 084 44 59 W |
| Twomile Run | Stream | | Muskingum | 40 10 36 N | 081 40 40 W |
| Twomile Run | Stream | | Muskingum | 39 49 52 N | 082 08 04 W |
| Twomile Run | Stream | | Vinton | 39 21 22 N | 082 23 05 W |
| Twomile Run | Stream | | Washington | 39 18 42 N | 081 50 58 W |
| Tycoon Lake | Reservoir | 182 | Gallia | 38 55 48 N | 082 20 60 W |
| Tycoon Lake | Reservoir | 187 | Gallia | 38 55 18 N | 082 21 12 W |
| Tycoon Lake - East Dam | Dam | 182 | Gallia | 38 55 48 N | 082 20 60 W |
| Tycoon Lake - South Dam | Dam | 187 | Gallia | 38 55 18 N | 082 21 12 W |
| Tycoon Lake State Wildlife Area | Park | 192 | Gallia | 38 55 38 N | 082 20 53 W |
| Tyler Airport | Airport | 152 | Brown | 38 40 00 N | 083 46 30 W |
| Tyler Cemetery | Cemetery | 280 | Highland | 39 18 49 N | 083 28 22 W |
| Tyler Cemetery | Cemetery | 286 | Highland | 39 20 27 N | 083 27 09 W |
| Tyler Davidson Fountain | Park | 168 | Hamilton | 39 06 05 N | 084 30 45 W |
| Tyler Digital Communications Center | Building | 319 | Greene | 39 44 48 N | 083 48 41 W |
| Tyler Field | Park | 185 | Cuyahoga | 41 27 47 N | 081 49 17 W |
| Tyler Memorial United Methodist Church | Church | 190 | Ross | 39 20 17 N | 082 59 28 W |
| Tylers Corners | Populated Place | 342 | Licking | 40 05 44 N | 082 39 47 W |
| Tylers Run | Stream | | Delaware | 40 09 07 N | 083 03 29 W |
| Tylersville | Populated Place | 263 | Butler | 39 21 27 N | 084 25 17 W |
| Tylersville Post Office (historical) | Post Office | 258 | Butler | 39 21 30 N | 084 25 15 W |
| Tymochtee | Populated Place | 240 | Wyandot | 40 56 57 N | 083 16 13 W |
| Tymochtee Creek | Stream | | Wyandot | 40 57 23 N | 083 16 03 W |
| Tymochtee School (historical) | School | 278 | Wyandot | 40 43 25 N | 083 28 39 W |
| Tyn Rhos Cemetery | Cemetery | 239 | Gallia | 38 51 14 N | 082 24 45 W |
| Tyn Rhos Church | Church | 237 | Gallia | 38 51 13 N | 082 24 47 W |
| Tyndal Methodist Church | Church | 234 | Coshocton | 40 13 02 N | 081 53 04 W |
| Tyndall | Populated Place | 233 | Coshocton | 40 13 02 N | 081 52 55 W |
| Tyndall Cemetery | Cemetery | 237 | Coshocton | 40 13 00 N | 081 53 03 W |
| Tyner | Populated Place | 238 | Guernsey | 40 06 19 N | 081 34 13 W |
| Tyner Post Office (historical) | Post Office | 241 | Guernsey | 40 06 20 N | 081 34 14 W |
| Tynrhos (historical) | Populated Place | 243 | Gallia | 38 51 28 N | 082 24 45 W |
| Tyre Baptist Church | Church | 240 | Hamilton | 39 07 52 N | 084 30 25 W |
| Tyrone | Populated Place | 335 | Coshocton | 40 15 10 N | 081 58 40 W |
| Tyrone Post Office (historical) | Post Office | 335 | Coshocton | 40 15 10 N | 081 58 39 W |
| Tyrrell | Populated Place | 346 | Trumbull | 41 16 20 N | 080 38 10 W |
| Tyrrell Post Office (historical) | Post Office | 346 | Trumbull | 41 16 20 N | 080 38 09 W |
| Tyson Run | Stream | | Morgan | 39 39 22 N | 081 44 26 W |
| Tytus Avenue First Church of God | Church | 203 | Butler | 39 32 16 N | 084 21 47 W |
| U Avenue and Hilock Freewill Baptist Church | Church | 228 | Franklin | 39 53 50 N | 082 58 33 W |
| U S Grant Middle School | School | 161 | Scioto | 38 44 01 N | 082 59 18 W |
| Ueltsch Run | Stream | | Monroe | 39 40 32 N | 080 52 02 W |
| Uhl Cemetery | Cemetery | 299 | Holmes | 40 31 48 N | 081 56 03 W |
| Uhl Run | Stream | | Holmes | 40 33 35 N | 081 56 49 W |
| Uhrichsville | Populated Place | 261 | Tuscarawas | 40 23 35 N | 081 20 47 W |
| Uhrichsville Post Office | Post Office | 262 | Tuscarawas | 40 23 30 N | 081 20 37 W |
| Uke Ranch Pond | Reservoir | 308 | Ashland | 41 03 24 N | 082 24 30 W |
| Uke Ranch Pond Dam | Dam | 308 | Ashland | 41 03 24 N | 082 24 30 W |
| Ukrainian National Hall | Building | 206 | Cuyahoga | 41 28 53 N | 081 41 28 W |
| Ukranian Youth Camp Lake | Reservoir | 262 | Lorain | 41 07 06 N | 082 15 30 W |
| Ukranian Youth Camp Lake Dam | Dam | 262 | Lorain | 41 07 06 N | 082 15 30 W |
| Ullman Cemetery | Cemetery | 348 | Holmes | 40 37 27 N | 082 12 03 W |
| Ulrey Run | Stream | | Clermont | 39 01 02 N | 084 09 10 W |
| Ulric | Populated Place | 247 | Meigs | 38 54 51 N | 081 51 39 W |
| Ulric Post Office (historical) | Post Office | 245 | Meigs | 38 54 50 N | 081 51 39 W |
| Ulrich Cemetery | Cemetery | 268 | Wyandot | 40 50 53 N | 083 11 29 W |
| Ulysses S Grant Elementary School | School | 308 | Mahoning | 41 05 41 N | 080 40 01 W |
| Umbrella Rock | Pillar | 297 | Tuscarawas | 40 19 27 N | 081 34 41 W |
| Umbria (historical) | Populated Place | 258 | Knox | 40 24 00 N | 082 11 25 W |
| Umbria Hall | Building | 201 | Lucas | 41 42 41 N | 083 42 24 W |
| Uncle Joes Chapel | Church | 246 | Jackson | 39 05 35 N | 082 25 59 W |
| Underhill Cemetery | Cemetery | 245 | Seneca | 41 12 41 N | 082 52 45 W |
| Underwood Cemetery | Cemetery | 348 | Highland | 39 17 55 N | 083 40 30 W |
| Underwood Cemetery | Cemetery | 298 | Marion | 40 35 00 N | 082 58 03 W |
| Unger Field | Airport | 287 | Highland | 39 21 35 N | 083 25 04 W |