Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Long Prairie | Area | 125 | Edwards | 38 20 35 N | 088 01 07 W |
| Long Prairie Cemetery | Cemetery | 284 | Boone | 42 23 33 N | 088 43 46 W |
| Long Prairie Church | Church | 133 | Jefferson | 38 16 31 N | 089 01 09 W |
| Long Prairie Church | Church | 142 | Wayne | 38 16 41 N | 088 40 31 W |
| Long Prairie Primitive Baptist Church | Church | 154 | Edwards | 38 31 07 N | 088 04 32 W |
| Long Prairie School (historical) | School | 137 | Clay | 38 39 41 N | 088 22 54 W |
| Long Prairie School (historical) | School | 142 | Franklin | 38 03 34 N | 088 50 04 W |
| Long Prairie School (historical) | School | 136 | Wabash | 38 32 25 N | 087 53 30 W |
| Long Prairie School (historical) | School | 138 | Wayne | 38 16 14 N | 088 40 29 W |
| Long Ridge | Ridge | 240 | Adams | 39 46 16 N | 090 55 41 W |
| Long RLA Airport | Airport | 209 | Warren | 40 39 51 N | 090 29 15 W |
| Long Run | Stream | | Will | 41 37 10 N | 088 03 39 W |
| Long Run Seep Nature Preserve | Park | 183 | Will | 41 37 25 N | 088 02 56 W |
| Long Shore Park | Populated Place | 138 | Peoria | 40 45 22 N | 089 33 39 W |
| Long Slash Creek | Stream | | Monroe | 38 20 40 N | 090 19 07 W |
| Long View Mine (historical) | Mine | 204 | Henry | 41 15 18 N | 090 22 48 W |
| Long View Park | Cape | 123 | Williamson | 37 43 58 N | 089 08 25 W |
| Longacre Park | Park | 178 | St. Clair | 38 34 57 N | 089 59 33 W |
| Longcommon Park | Park | 188 | Cook | 41 50 03 N | 087 48 57 W |
| Longfellow Elementary School | School | 219 | Cook | 42 08 41 N | 087 59 02 W |
| Longfellow Elementary School | School | 232 | DuPage | 41 52 04 N | 088 06 37 W |
| Longfellow Elementary School | School | 177 | Rock Island | 41 30 16 N | 090 32 36 W |
| Longfellow Elementary School | School | 133 | Williamson | 37 43 21 N | 088 56 35 W |
| Longfellow Park | Park | 188 | Cook | 41 52 38 N | 087 47 00 W |
| Longfellow School | School | 182 | Cook | 41 49 47 N | 087 40 22 W |
| Longfellow School | School | 188 | Cook | 41 52 32 N | 087 46 56 W |
| Longfellow School | School | 206 | Cook | 41 52 49 N | 087 54 49 W |
| Longfellow School | School | 221 | DuPage | 41 47 59 N | 088 01 13 W |
| Longfellow School | School | 125 | Jackson | 37 46 04 N | 089 20 49 W |
| Longfellow School | School | 155 | Peoria | 40 42 26 N | 089 34 28 W |
| Longfellow School (historical) | School | 239 | Stark | 41 11 59 N | 089 44 42 W |
| Longjohn Slough | Gut | 212 | Cook | 41 42 46 N | 087 52 44 W |
| Longmeadow Activity Center | Building | 241 | Cook | 42 00 10 N | 088 08 08 W |
| Longmire School (historical) | School | 206 | Livingston | 40 51 46 N | 088 18 00 W |
| Longs Lake | Reservoir | 173 | Cass | 40 02 12 N | 090 07 18 W |
| Longs Lake Dam | Dam | 173 | Cass | 40 02 12 N | 090 07 18 W |
| Longshore School (historical) | School | 197 | Iroquois | 40 44 48 N | 087 44 53 W |
| Longsworth Cemetery | Cemetery | 201 | McLean | 40 19 26 N | 089 14 13 W |
| Longtown Ferry (historical) | Locale | 125 | Crawford | 38 54 05 N | 087 32 00 W |
| Longview | Populated Place | 207 | Champaign | 39 53 12 N | 088 03 59 W |
| Longview Airport | Airport | 218 | La Salle | 41 23 16 N | 088 40 12 W |
| Longview Estates | Populated Place | 246 | Kane | 41 57 02 N | 088 20 10 W |
| Longview Park | Park | 206 | Lake | 42 10 09 N | 087 47 08 W |
| Longview Park | Park | 200 | Rock Island | 41 29 44 N | 090 34 31 W |
| Longview Place (subdivision) | Populated Place | 205 | Macon | 39 51 07 N | 088 56 50 W |
| Longview School (historical) | School | 207 | Iroquois | 40 43 14 N | 088 06 21 W |
| Longwill Cemetery | Cemetery | 178 | Jersey | 39 09 35 N | 090 11 31 W |
| Longwood Country Club | Locale | 206 | Will | 41 27 55 N | 087 31 37 W |
| Longwood Elementary School | School | 190 | Cook | 41 33 17 N | 087 37 50 W |
| Longwood Elementary School | School | 218 | DuPage | 41 47 26 N | 088 12 41 W |
| Loogootee | Populated Place | 184 | Fayette | 38 54 17 N | 088 51 13 W |
| Loogootee Post Office | Post Office | 184 | Fayette | 38 54 17 N | 088 51 14 W |
| Lookout Point | Summit | 243 | Winnebago | 42 17 00 N | 089 03 45 W |
| Lookout Point Picnic Area | Locale | 160 | Marion | 38 42 43 N | 088 45 02 W |
| Lookout Point Picnic Area | Locale | 151 | Washington | 38 16 11 N | 089 21 22 W |
| Lookout Rocks | Summit | 159 | Jackson | 37 39 18 N | 089 24 32 W |
| Lookout School (historical) | School | 184 | Cumberland | 39 15 02 N | 088 20 30 W |
| Lookout School (historical) | School | 195 | Fulton | 40 11 53 N | 090 17 03 W |
| Loomis Laboratory | Building | 217 | Champaign | 40 06 39 N | 088 13 23 W |
| Loon Lake | Lake | 235 | Lake | 42 27 10 N | 088 05 00 W |
| Loon Lake | Lake | 96 | Massac | 37 06 12 N | 088 34 47 W |
| Loon Lake | Populated Place | 238 | Lake | 42 26 49 N | 088 05 24 W |
| Loon Lake | Reservoir | 179 | Kendall | 41 37 51 N | 088 31 26 W |
| Looney Springs Cemetery | Cemetery | 166 | Jackson | 37 55 32 N | 089 32 28 W |
| Loop Campus DePaul University | School | 182 | Cook | 41 52 40 N | 087 37 40 W |
| Loop College | School | 183 | Cook | 41 53 09 N | 087 37 32 W |
| Loop Creek | Stream | | St. Clair | 38 28 25 N | 089 49 41 W |
| Loop Evangelical Free Church | Church | 188 | Cook | 41 52 19 N | 087 46 43 W |
| Loop Station Chicago Post Office | Post Office | 181 | Cook | 41 52 44 N | 087 37 49 W |
| Loos School | School | 156 | Madison | 38 47 42 N | 089 49 19 W |
| Loos School (historical) | School | 156 | Madison | 38 47 42 N | 089 49 19 W |
| Loose Pulley Junction | Populated Place | 214 | Ogle | 42 07 34 N | 089 13 26 W |
| Loraine | Populated Place | 196 | Adams | 40 09 15 N | 091 13 21 W |
| Loraine Cemetery | Cemetery | 188 | Henry | 41 34 21 N | 090 02 45 W |
| Loraine Elementary School | School | 196 | Adams | 40 09 23 N | 091 13 26 W |
| Loraine New Cemetery | Cemetery | 190 | Adams | 40 08 48 N | 091 13 50 W |
| Loraine Old Cemetery | Cemetery | 195 | Adams | 40 09 20 N | 091 13 06 W |
| Loraine Quarry | Mine | 178 | Adams | 40 07 16 N | 091 12 18 W |
| Loraine School (historical) | School | 188 | Henry | 41 33 56 N | 090 03 03 W |
| Loraine United Methodist Church | Church | 188 | Henry | 41 33 57 N | 090 03 01 W |
| Loran | Populated Place | 232 | Stephenson | 42 14 06 N | 089 54 37 W |
| Lord and Savior Evangelical Lutheran Church | Church | 285 | McHenry | 42 16 06 N | 088 22 42 W |
| Lord of Host Missionary Baptist Church | Church | 184 | Cook | 41 53 43 N | 087 42 46 W |
| Lord of Life Lutheran Church | Church | 225 | DuPage | 41 45 06 N | 087 57 35 W |
| Lords House of Prayer | Church | 183 | Cook | 41 47 13 N | 087 37 33 W |
| Lords Lutheran Church | Church | 175 | Madison | 38 42 40 N | 089 57 33 W |
| Lords Park | Park | 238 | Cook | 42 02 30 N | 088 15 38 W |
| Lords Park Elementary School | School | 243 | Cook | 42 02 37 N | 088 15 08 W |
| Lorel Park | Park | 190 | Cook | 42 01 45 N | 087 45 36 W |
| Lorelei Acres Park | Park | 219 | Lake | 42 28 24 N | 087 52 11 W |
| Lorenz Brentano Playground | Park | 181 | Cook | 41 55 50 N | 087 41 44 W |
| Lorenzo | Populated Place | 163 | Will | 41 20 50 N | 088 12 56 W |
| Loretta Adult Education Center | School | 181 | Cook | 41 46 36 N | 087 35 22 W |
| Loretta Home for Working Girls | Building | 180 | Madison | 38 53 41 N | 090 11 26 W |
| Loretto | Populated Place | 216 | Livingston | 40 58 40 N | 088 26 05 W |
| Loretto Convent | School | 235 | DuPage | 41 50 22 N | 088 06 56 W |
| Lori-Sue Subdivision | Populated Place | 160 | Grundy | 41 20 18 N | 088 23 45 W |
| Lorimer School | School | 184 | Cook | 41 37 31 N | 087 35 10 W |
| Loring School (historical) | School | 207 | La Salle | 41 22 06 N | 088 42 18 W |
| Lorraine Gray Dance Studio | School | 181 | Cook | 41 48 56 N | 087 42 04 W |
| Lorton Bridge | Bridge | 153 | Fayette | 39 10 41 N | 088 53 41 W |
| Lorton Cemetery | Cemetery | 179 | Fayette | 39 11 29 N | 088 53 50 W |
| Lorton Church (historical) | Church | 180 | Fayette | 39 11 29 N | 088 53 57 W |
| Lorusso Lagoon | Reservoir | 265 | DeKalb | 41 56 20 N | 088 46 41 W |
| Lost Branch | Stream | | Perry | 38 08 00 N | 089 21 39 W |
| Lost Branch | Stream | | Williamson | 37 40 30 N | 089 05 52 W |
| Lost Bridge | Bridge | 187 | Macon | 39 49 13 N | 088 55 35 W |
| Lost Creek | Stream | | Cass | 40 01 54 N | 090 21 44 W |
| Lost Creek | Stream | | Clinton | 38 31 01 N | 089 20 52 W |
| Lost Creek | Stream | | Cumberland | 39 16 17 N | 088 09 39 W |