Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Slabcamp School (historical) | School | 308 | Brown | 38 58 44 N | 083 47 01 W |
| Slabtown | Populated Place | 260 | Allen | 40 47 20 N | 084 03 07 W |
| Slagle Cemetery | Cemetery | 207 | Vinton | 39 19 48 N | 082 38 35 W |
| Slagle Farm Cemetery | Cemetery | 226 | Vinton | 39 19 41 N | 082 38 37 W |
| Slankers Mill (historical) | Locale | 287 | Stark | 40 50 45 N | 081 31 54 W |
| Slate Fork Churn Creek | Stream | | Adams | 38 44 02 N | 083 18 15 W |
| Slate Hill | Summit | 385 | Highland | 39 08 03 N | 083 26 22 W |
| Slate Hill | Summit | 375 | Ross | 39 15 23 N | 083 19 32 W |
| Slate Hill | Summit | 376 | Ross | 39 22 39 N | 083 16 57 W |
| Slate Hill School (historical) | School | 293 | Highland | 39 07 54 N | 083 26 54 W |
| Slate Hollow | Valley | | Scioto | 38 44 04 N | 083 11 35 W |
| Slate Lick | Stream | | Delaware | 40 18 46 N | 082 56 43 W |
| Slate Mills | Populated Place | 201 | Ross | 39 21 02 N | 083 03 26 W |
| Slate Mills Post Office (historical) | Post Office | 211 | Ross | 39 21 00 N | 083 03 25 W |
| Slate Run | Stream | | Franklin | 40 03 08 N | 083 05 46 W |
| Slate Run | Stream | | Huron | 41 13 00 N | 082 42 09 W |
| Slate Run | Stream | | Lawrence | 38 30 16 N | 082 23 47 W |
| Slate Run | Stream | | Pickaway | 39 47 10 N | 082 52 55 W |
| Slate Run | Stream | | Ross | 39 18 28 N | 083 20 11 W |
| Slate Run | Stream | | Scioto | 38 50 16 N | 083 10 49 W |
| Slate Run | Stream | | Scioto | 38 53 42 N | 083 01 26 W |
| Slate Run Living Historical Farm | Locale | 269 | Pickaway | 39 45 14 N | 082 50 59 W |
| Slate Run Metropolitan Park | Park | 253 | Pickaway | 39 45 38 N | 082 51 08 W |
| Slate School (historical) | School | 229 | Van Wert | 40 55 02 N | 084 28 32 W |
| Slater | Populated Place | 309 | Auglaize | 40 31 40 N | 084 04 24 W |
| Slater Brothers Pond | Reservoir | 226 | Athens | 39 21 12 N | 082 07 12 W |
| Slater Brothers Pond Dam | Dam | 226 | Athens | 39 21 12 N | 082 07 12 W |
| Slater Ditch | Canal | 212 | Lorain | 41 25 12 N | 082 01 10 W |
| Slater Run | Stream | | Richland | 40 35 46 N | 082 24 49 W |
| Slaters | Populated Place | 242 | Noble | 39 45 56 N | 081 32 21 W |
| Slates Dam | Dam | 368 | Columbiana | 40 45 30 N | 080 54 05 W |
| Slates Reservoir | Reservoir | 368 | Columbiana | 40 45 30 N | 080 54 05 W |
| Slaty Hollow | Valley | | Logan | 40 19 14 N | 083 39 11 W |
| Slaughter Hill School (historical) | School | 331 | Guernsey | 40 02 58 N | 081 32 56 W |
| Slaughter School (historical) | School | 331 | Madison | 39 43 51 N | 083 32 51 W |
| Slaughterhouse Run | Stream | | Belmont | 40 04 05 N | 080 45 45 W |
| Slavens Cemetery | Cemetery | 234 | Pike | 38 57 38 N | 082 53 30 W |
| Slavic Village | Populated Place | 213 | Cuyahoga | 41 27 22 N | 081 38 41 W |
| Slayter Hall Student Union | Building | 333 | Licking | 40 04 16 N | 082 31 26 W |
| Slee Ditch | Canal | 268 | Seneca | 41 01 34 N | 083 03 49 W |
| Sleepy Hollow | Valley | | Muskingum | 39 47 40 N | 081 45 35 W |
| Sleepy Hollow Acres | Populated Place | 270 | Mercer | 40 32 42 N | 084 32 44 W |
| Sleepy Hollow Airport | Airport | 343 | Stark | 40 47 01 N | 081 05 56 W |
| Sleepy Hollow Golf Course | Locale | 282 | Cuyahoga | 41 18 20 N | 081 37 13 W |
| Sleepy Hollow Golf Course | Locale | 209 | Sandusky | 41 20 28 N | 082 53 58 W |
| Sleepy Hollow School (historical) | School | 267 | Muskingum | 39 48 10 N | 081 45 14 W |
| Slemmons Creek | Stream | | Morgan | 39 39 07 N | 081 51 45 W |
| Slickaway | Populated Place | 186 | Brown | 38 41 01 N | 083 44 47 W |
| Slickaway Hollow | Valley | | Ross | 39 23 09 N | 082 47 20 W |
| Slickaway Run | Stream | | Brown | 38 40 36 N | 083 45 01 W |
| Slickaway Run | Stream | | Clermont | 38 48 20 N | 084 03 22 W |
| Slickaway School (historical) | School | 316 | Highland | 39 22 04 N | 083 34 49 W |
| Slifer Cemetery | Cemetery | 271 | Montgomery | 39 41 58 N | 084 23 45 W |
| Slifers Presbyterian Church | Church | 271 | Montgomery | 39 42 00 N | 084 23 44 W |
| Sligo | Populated Place | 298 | Clinton | 39 26 30 N | 083 55 13 W |
| Sligo School (historical) | School | 337 | Guernsey | 40 11 10 N | 081 23 52 W |
| Slim Creek | Stream | | Licking | 39 57 07 N | 082 35 09 W |
| Slingluff Park | Park | 275 | Tuscarawas | 40 31 42 N | 081 28 51 W |
| Slipper Run | Stream | | Summit | 41 14 35 N | 081 33 13 W |
| Slippery Point School (historical) | School | 256 | Wyandot | 40 51 41 N | 083 19 25 W |
| Slitor Cemetery | Cemetery | 354 | Geauga | 41 25 34 N | 081 08 33 W |
| Sloan Cemetery | Cemetery | 372 | Monroe | 39 42 07 N | 081 11 48 W |
| Sloan Cemetery | Cemetery | 396 | Monroe | 39 51 34 N | 081 10 32 W |
| Sloan Run | Stream | | Belmont | 40 07 27 N | 080 52 40 W |
| Sloan-Yelverton Cemetery | Cemetery | 332 | Hardin | 40 32 20 N | 083 43 07 W |
| Sloas Airport | Airport | 265 | Trumbull | 41 16 00 N | 080 45 59 W |
| Slocum | Populated Place | 163 | Scioto | 38 45 59 N | 082 50 33 W |
| Slocum Cemetery | Cemetery | 169 | Scioto | 38 45 57 N | 082 49 42 W |
| Slocum Elementary School | School | 212 | Defiance | 41 16 57 N | 084 21 60 W |
| Slocum Hall | Building | 269 | Delaware | 40 17 46 N | 083 04 01 W |
| Slocum Heights | Populated Place | 173 | Scioto | 38 46 14 N | 082 50 59 W |
| Slocum Station Church | Church | 167 | Scioto | 38 45 51 N | 082 50 24 W |
| Slope Church | Church | 356 | Trumbull | 41 12 47 N | 080 33 10 W |
| Slope Creek | Stream | | Belmont | 39 53 46 N | 081 08 37 W |
| Slope Hollow | Valley | | Lawrence | 38 37 01 N | 082 39 16 W |
| Slough | Populated Place | 297 | Fairfield | 39 47 58 N | 082 45 42 W |
| Slough Cemetery | Cemetery | 222 | Paulding | 41 12 14 N | 084 42 52 W |
| Slough Post Office (historical) | Post Office | 303 | Fairfield | 39 48 00 N | 082 45 40 W |
| Slough School (historical) | School | 368 | Licking | 40 02 17 N | 082 38 43 W |
| Slovak Evangelical Cemetery | Cemetery | 337 | Summit | 41 00 47 N | 081 28 03 W |
| Slovene Home for the Aged | Building | 186 | Cuyahoga | 41 34 56 N | 081 32 56 W |
| Slovenia Hall | Building | 190 | Cuyahoga | 41 33 36 N | 081 34 12 W |
| Sludge Basin Lights | Locale | 174 | Erie | 41 27 37 N | 082 41 48 W |
| Slurry Impoundments 3, 3a, 3b | Reservoir | 207 | Monroe | 39 43 12 N | 080 52 47 W |
| Slutz Cemetery | Cemetery | 348 | Holmes | 40 38 49 N | 081 47 49 W |
| Slutz Cemetery | Cemetery | 322 | Stark | 40 42 16 N | 081 32 52 W |
| Slyman Lake | Reservoir | 328 | Ashland | 40 57 42 N | 082 15 36 W |
| Slyman Lake Dam | Dam | 328 | Ashland | 40 57 42 N | 082 15 36 W |
| Small Atkinson Creek | Stream | | Harrison | 40 12 51 N | 081 19 40 W |
| Small Middle Run | Stream | | Tuscarawas | 40 35 53 N | 081 24 52 W |
| Smalley Cemetery | Cemetery | 235 | Butler | 39 25 25 N | 084 27 51 W |
| Smalley Playfield | Park | 253 | Butler | 39 24 48 N | 084 37 02 W |
| Smalls Landing | Locale | 159 | Gallia | 38 38 41 N | 082 10 43 W |
| Smallwood School (historical) | School | 195 | Vinton | 39 13 02 N | 082 44 05 W |
| Smeizer Cemetery | Cemetery | 223 | Hamilton | 39 17 14 N | 084 23 44 W |
| Smeltzer Cemetery | Cemetery | 347 | Ashland | 40 50 23 N | 082 23 12 W |
| Smiley (historical) | Populated Place | 231 | Paulding | 41 04 39 N | 084 47 39 W |
| Smiley Cemetery | Cemetery | 230 | Hamilton | 39 18 20 N | 084 32 34 W |
| Smiley Ditch | Canal | 228 | Paulding | 41 05 24 N | 084 47 38 W |
| Smiley Park | Park | 238 | Van Wert | 40 52 05 N | 084 36 28 W |
| Smiley Post Office (historical) | Post Office | 230 | Paulding | 41 04 40 N | 084 47 40 W |
| Smiley School (historical) | School | 229 | Paulding | 41 04 33 N | 084 47 05 W |
| Smith (historical) | Populated Place | 227 | Muskingum | 39 53 21 N | 081 48 11 W |
| Smith Avenue First Church of God | Church | 198 | Butler | 39 29 40 N | 084 23 55 W |
| Smith Branch | Stream | | Highland | 39 10 13 N | 083 29 19 W |
| Smith Cemetery | Cemetery | 293 | Allen | 40 40 46 N | 083 58 35 W |
| Smith Cemetery | Cemetery | 254 | Allen | 40 47 18 N | 084 04 49 W |
| Smith Cemetery | Cemetery | 344 | Champaign | 40 03 12 N | 084 01 17 W |
| Smith Cemetery | Cemetery | 231 | Fulton | 41 35 45 N | 084 13 54 W |
| Smith Cemetery | Cemetery | 200 | Gallia | 38 41 26 N | 082 16 11 W |