Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Smith School (historical) | School | 190 | Montgomery | 39 02 52 N | 089 38 34 W |
| Smith School (historical) | School | 246 | Ogle | 41 57 24 N | 089 00 03 W |
| Smith School (historical) | School | 140 | Pike | 39 38 58 N | 091 14 35 W |
| Smith School (historical) | School | 121 | Saline | 37 48 56 N | 088 33 13 W |
| Smith School (historical) | School | 196 | Shelby | 39 25 03 N | 088 56 08 W |
| Smith School (historical) | School | 125 | White | 38 06 42 N | 088 16 54 W |
| Smith School (historical) | School | 191 | Will | 41 37 26 N | 088 09 13 W |
| Smith School (historical) | School | 265 | Winnebago | 42 18 16 N | 089 15 43 W |
| Smith Woods | Woods | 187 | Cook | 42 00 16 N | 087 47 29 W |
| Smithboro | Populated Place | 170 | Bond | 38 53 46 N | 089 20 26 W |
| Smithdale | Populated Place | 188 | Livingston | 41 05 05 N | 088 46 30 W |
| Smithdale School (historical) | School | 186 | Livingston | 41 05 23 N | 088 47 20 W |
| Smithfield | Populated Place | 197 | Fulton | 40 28 24 N | 090 17 30 W |
| Smithfield School (historical) | School | 195 | Fulton | 40 28 31 N | 090 17 36 W |
| Smithland Lock One Dam | Dam | 102 | Pope | 37 25 20 N | 088 25 47 W |
| Smiths Branch | Stream | | Macon | 39 48 47 N | 089 02 41 W |
| Smiths Island | Island | 168 | Rock Island | 41 28 08 N | 090 35 43 W |
| Smiths Mound | Summit | 228 | Livingston | 41 03 37 N | 088 41 22 W |
| Smiths Park | Park | 169 | Rock Island | 41 27 52 N | 090 35 37 W |
| Smithshire | Populated Place | 224 | Warren | 40 47 34 N | 090 46 47 W |
| Smithshire Post Office | Post Office | 224 | Warren | 40 47 32 N | 090 46 43 W |
| Smithson Cemetery | Cemetery | 165 | Scott | 39 39 44 N | 090 31 04 W |
| Smithton | Populated Place | 145 | St. Clair | 38 24 31 N | 089 59 31 W |
| Smithton City Hall | Building | 144 | St. Clair | 38 24 28 N | 089 59 32 W |
| Smithton Community Park | Park | 131 | St. Clair | 38 24 06 N | 089 57 45 W |
| Smithton Post Office | Post Office | 145 | St. Clair | 38 24 33 N | 089 59 30 W |
| Smithton School | School | 143 | St. Clair | 38 24 21 N | 089 59 27 W |
| Smithton Sportmans Club Lake | Reservoir | 140 | St. Clair | 38 22 36 N | 090 01 00 W |
| Smithton Sportmans Club Lake Dam | Dam | 140 | St. Clair | 38 22 36 N | 090 01 00 W |
| Smithton-Franklin Cemetery | Cemetery | 143 | St. Clair | 38 24 12 N | 089 59 37 W |
| Smithville | Populated Place | 215 | Peoria | 40 39 37 N | 089 47 59 W |
| Smithville | Populated Place | 131 | Wayne | 38 16 14 N | 088 35 30 W |
| Smithville Cemetery | Cemetery | 213 | Peoria | 40 39 48 N | 089 48 15 W |
| Smittys Airport (historical) | Airport | 244 | Tazewell | 40 43 28 N | 089 24 43 W |
| Smoky Row School (historical) | School | 198 | Montgomery | 39 15 42 N | 089 13 30 W |
| Smoot Cemetery | Cemetery | 168 | Menard | 40 03 49 N | 089 48 36 W |
| Smothers Cemetery | Cemetery | 130 | Franklin | 37 54 55 N | 088 48 55 W |
| Smothersville | Populated Place | 143 | Franklin | 37 57 15 N | 088 50 26 W |
| Smutzlar Siding | Locale | 189 | Macoupin | 39 03 37 N | 089 48 31 W |
| Smyer Old Cemetery | Cemetery | 145 | Moultrie | 38 30 12 N | 088 31 20 W |
| Smyra Missionary Baptist Church | Church | 188 | Cook | 41 45 31 N | 087 48 04 W |
| Smyrna Cemetery | Cemetery | 190 | Hardin | 37 30 13 N | 088 09 29 W |
| Smyrna Cemetery | Cemetery | 196 | Sangamon | 39 39 50 N | 089 53 45 W |
| Smyrna Korean Presbyterian Church | Church | 187 | Cook | 41 56 03 N | 087 44 55 W |
| Smyser Church | Church | 200 | Moultrie | 39 30 09 N | 088 31 23 W |
| Smyser Elementary School | School | 190 | Cook | 41 57 34 N | 087 46 58 W |
| Smysor School (historical) | School | 200 | Moultrie | 39 30 10 N | 088 31 37 W |
| Smyth Elementary School | School | 181 | Cook | 41 51 54 N | 087 39 11 W |
| Snag Creek | Stream | | Woodford | 40 55 08 N | 089 26 26 W |
| Snag Lake | Lake | 158 | Henderson | 40 46 29 N | 091 05 06 W |
| Snake Creek | Stream | | Edgar | 39 42 46 N | 087 38 30 W |
| Snake Creek | Stream | | Mercer | 41 05 03 N | 090 47 24 W |
| Snake Creek | Stream | | Morgan | 39 49 12 N | 090 13 56 W |
| Snake Creek | Stream | | Woodford | 40 54 03 N | 089 14 01 W |
| Snake Island | Island | 228 | Lake | 42 13 43 N | 088 09 04 W |
| Snake Trail Campground Lake | Reservoir | 187 | Clark | 39 20 48 N | 087 54 36 W |
| Snake Trail Campground Lake Dam | Dam | 187 | Clark | 39 20 48 N | 087 54 36 W |
| Snakeden Branch | Stream | | Clark | 39 27 15 N | 087 48 29 W |
| Snakeden Branch | Stream | | McDonough | 40 15 49 N | 090 30 20 W |
| Snakeden Hollow | Valley | | Knox | 40 57 56 N | 090 04 37 W |
| Snakeden Hollow Lake | Reservoir | 229 | Knox | 41 00 23 N | 090 04 10 W |
| Snakeden Hollow State Fish and Wildlife Area | Park | 230 | Knox | 41 00 42 N | 090 04 50 W |
| Snapper Field Park | Park | 251 | McHenry | 42 09 27 N | 088 16 53 W |
| Snareville Cemetery | Cemetery | 214 | Stark | 41 06 46 N | 089 45 04 W |
| Snareville School (historical) | School | 218 | Stark | 41 06 43 N | 089 45 01 W |
| Snearlyville | Populated Place | 132 | Clinton | 38 36 36 N | 089 29 42 W |
| Snedeker Grove School (historical) | School | 187 | Macoupin | 39 07 47 N | 089 58 43 W |
| Sneed Cemetery | Cemetery | 162 | Hardin | 37 33 59 N | 088 20 47 W |
| Sneed Church | Church | 141 | Hamilton | 38 03 32 N | 088 25 26 W |
| Sneed School (historical) | School | 141 | Hamilton | 38 03 35 N | 088 25 11 W |
| Sneider Landing Strip | Airport | 131 | Brown | 39 54 10 N | 090 34 28 W |
| Snell Baseball Field | Park | 210 | Kane | 41 45 13 N | 088 21 05 W |
| Snell Hall | Building | 180 | Cook | 41 47 28 N | 087 36 04 W |
| Snicarte | Populated Place | 135 | Mason | 40 07 24 N | 090 13 53 W |
| Snicarte Cemetery | Cemetery | 136 | Mason | 40 07 10 N | 090 13 11 W |
| Snicarte Island | Island | 134 | Mason | 40 08 51 N | 090 12 10 W |
| Snicarte Slough | Gut | 132 | Mason | 40 07 54 N | 090 12 35 W |
| Snider | Populated Place | 210 | Vermilion | 40 12 15 N | 087 41 52 W |
| Snider Cemetery | Cemetery | 208 | Vermilion | 40 09 15 N | 087 42 57 W |
| Snider Hill Cemetery | Cemetery | 152 | Jackson | 37 42 55 N | 089 11 56 W |
| Snider Lake | Lake | 114 | Jackson | 37 54 20 N | 089 10 44 W |
| Snider School (historical) | School | 215 | Vermilion | 40 11 44 N | 087 47 52 W |
| Snipe Hollow | Valley | | Jo Daviess | 42 20 31 N | 090 15 30 W |
| Snockey Pond | Lake | 106 | Saline | 37 42 16 N | 088 24 27 W |
| Snow Airport | Airport | 222 | Macon | 39 44 59 N | 088 58 46 W |
| Snow Cemetery | Cemetery | 200 | Bond | 39 00 44 N | 089 19 29 W |
| Snow Creek | Stream | | Jefferson | 38 22 24 N | 089 01 18 W |
| Snow Hill Cemetery | Cemetery | 148 | Marion | 38 34 35 N | 088 47 30 W |
| Snow Hill School (historical) | School | 244 | Henry | 41 09 59 N | 090 13 40 W |
| Snow Park | Park | 199 | Kankakee | 41 07 12 N | 087 51 01 W |
| Snow RLA Airport | Airport | 244 | McLean | 40 32 29 N | 088 49 17 W |
| Snowhill Church | Church | 150 | Marion | 38 34 35 N | 088 47 29 W |
| Snowhill School (historical) | School | 142 | Marion | 38 34 35 N | 088 46 51 W |
| Sny Church (historical) | Church | 135 | Pike | 39 27 46 N | 090 59 18 W |
| Snyder | Populated Place | 169 | Clark | 39 16 57 N | 087 40 03 W |
| Snyder Cemetery | Cemetery | 153 | Marion | 38 32 12 N | 089 05 26 W |
| Snyder Creek | Stream | | Clark | 39 14 33 N | 087 34 49 W |
| Snyder Grove Park | Park | 211 | La Salle | 41 31 17 N | 089 05 20 W |
| Snyder Hall | Building | 226 | Champaign | 40 06 07 N | 088 14 06 W |
| Snyder Lake | Lake | 141 | Adams | 39 51 15 N | 091 24 48 W |
| Snyder Park | Park | 204 | Lake | 42 10 01 N | 087 47 08 W |
| Snyder Pond | Swamp | 135 | Pike | 39 26 17 N | 090 55 45 W |
| Snyder School (historical) | School | 136 | Clay | 38 44 51 N | 088 18 47 W |
| Snyder School (historical) | School | 119 | Jackson | 37 48 15 N | 089 11 20 W |
| Snyder School (historical) | School | 207 | Schuyler | 40 15 21 N | 090 37 35 W |
| Snyder School (historical) | School | 200 | Vermilion | 39 56 55 N | 087 42 34 W |
| Social Science Research Building | Building | 180 | Cook | 41 47 16 N | 087 35 56 W |
| Society of Friends Fifty-Seventh Street Meeting Hall | Church | 180 | Cook | 41 47 33 N | 087 35 47 W |
| Socrates Greek-American Elementary School | School | 190 | Cook | 41 55 51 N | 087 46 39 W |
| Sodom School (historical) | School | 211 | Adams | 39 46 45 N | 091 14 29 W |