Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Lynn Cemetery | Cemetery | 167 | Schuyler | 40 06 55 N | 090 42 28 W |
| Lynn Center | Populated Place | 231 | Henry | 41 17 45 N | 090 21 28 W |
| Lynn Center Cemetery | Cemetery | 220 | Henry | 41 18 10 N | 090 21 29 W |
| Lynn Creek | Stream | | Moultrie | 39 30 32 N | 088 32 12 W |
| Lynn Creek | Stream | | Whiteside | 41 43 34 N | 090 01 26 W |
| Lynn Creek Cemetery | Cemetery | 199 | Moultrie | 39 29 56 N | 088 33 11 W |
| Lynn G Haskin Elementary School | School | 201 | DeKalb | 41 38 22 N | 088 37 09 W |
| Lynn Grove | Woods | 216 | Henry | 41 18 10 N | 090 23 05 W |
| Lynn Grove Branch | Stream | | Macoupin | 39 22 15 N | 089 45 58 W |
| Lynn Grove Cemetery | Cemetery | 222 | Champaign | 39 58 06 N | 088 06 49 W |
| Lynn Grove Methodist Episcopal Church (historical) | Church | 211 | McDonough | 40 35 10 N | 090 34 42 W |
| Lynn Grove School (historical) | School | 184 | Logan | 40 03 55 N | 089 32 26 W |
| Lynn Grove School (historical) | School | 198 | Macoupin | 39 22 12 N | 089 47 10 W |
| Lynn Grove School (historical) | School | 210 | McDonough | 40 35 10 N | 090 34 44 W |
| Lynn Grove School (historical) | School | 125 | Wayne | 38 22 11 N | 088 23 59 W |
| Lynn Plaza Shopping Center | Locale | 198 | Cook | 42 08 25 N | 087 55 48 W |
| Lynn School (historical) | School | 216 | Brown | 39 54 24 N | 090 52 26 W |
| Lynn School (historical) | School | 150 | Cass | 40 04 17 N | 090 01 14 W |
| Lynn School (historical) | School | 176 | Schuyler | 40 02 38 N | 090 37 35 W |
| Lynndora School (historical) | School | 184 | Sangamon | 39 32 21 N | 089 32 07 W |
| Lynnville | Populated Place | 189 | Morgan | 39 41 13 N | 090 20 45 W |
| Lynnville Cemetery | Cemetery | 189 | Morgan | 39 41 28 N | 090 20 16 W |
| Lynnville Election Precinct | Civil | 192 | Morgan | 39 40 53 N | 090 20 12 W |
| Lynnville School (historical) | School | 207 | Henderson | 40 52 32 N | 090 54 45 W |
| Lynnwood Lake | Reservoir | 223 | Henry | 41 18 42 N | 090 23 12 W |
| Lynnwood Lake Dam | Dam | 223 | Henry | 41 18 42 N | 090 23 12 W |
| Lynwood | Populated Place | 188 | Cook | 41 31 35 N | 087 32 19 W |
| Lynwood | Populated Place | 198 | Kendall | 41 41 01 N | 088 23 37 W |
| Lynwood Baptist Church | Church | 197 | Kendall | 41 40 47 N | 088 23 37 W |
| Lynwood Christian Reform Church | Church | 189 | Cook | 41 31 47 N | 087 34 08 W |
| Lyon County Forest Preserve | Park | 197 | Kendall | 41 38 27 N | 088 24 51 W |
| Lyon Elementary School | School | 194 | Cook | 42 04 44 N | 087 47 49 W |
| Lyon Lakes | Lake | 255 | Lee | 41 41 00 N | 089 16 12 W |
| Lyon Magnet Elementary School | School | 201 | Lake | 42 20 38 N | 087 51 18 W |
| Lyon School | School | 190 | Cook | 41 56 03 N | 087 46 37 W |
| Lyon School (historical) | School | 204 | Lee | 41 40 19 N | 089 32 11 W |
| Lyons | Populated Place | 189 | Cook | 41 48 48 N | 087 49 05 W |
| Lyons Cemetery | Cemetery | 198 | Fulton | 40 41 27 N | 090 11 10 W |
| Lyons Dam | Dam | 186 | Cook | 41 49 12 N | 087 49 30 W |
| Lyons Evangelical Free Church | Church | 189 | Cook | 41 48 56 N | 087 49 09 W |
| Lyons Lake | Lake | 134 | Putnam | 41 18 27 N | 089 17 40 W |
| Lyons North High School | School | 197 | Cook | 41 48 41 N | 087 52 48 W |
| Lyons Park | Park | 207 | Macon | 39 50 13 N | 088 55 45 W |
| Lyons Post Office | Post Office | 185 | Cook | 41 49 12 N | 087 49 03 W |
| Lyons Public Library | Building | 189 | Cook | 41 48 53 N | 087 49 13 W |
| Lyons Quarry | Mine | 129 | Cook | 41 48 52 N | 087 49 51 W |
| Lyons School (historical) | School | 257 | Kane | 41 52 50 N | 088 30 03 W |
| Lyons School (historical) | School | 293 | McHenry | 42 28 07 N | 088 27 43 W |
| Lyons South High School | School | 207 | Cook | 41 48 04 N | 087 53 27 W |
| Lyons Village Hall | Building | 185 | Cook | 41 49 11 N | 087 48 57 W |
| Lyons Woods Forest Preserve | Park | 200 | Lake | 42 24 05 N | 087 50 19 W |
| Lyons-Fulton Bridge | Bridge | 174 | Whiteside | 41 52 06 N | 090 10 13 W |
| Lyonsville Church | Church | 203 | Cook | 41 45 57 N | 087 53 45 W |
| Lytle Park | Park | 222 | Coles | 39 28 53 N | 088 23 53 W |
| Lytleville Orchard Airport | Airport | 239 | McLean | 40 20 04 N | 088 57 19 W |
| Lytleville School (historical) | School | 223 | McLean | 40 20 27 N | 088 57 22 W |
| M A Montgomery Memorial Sanitarium | Hospital | 206 | Coles | 39 29 32 N | 088 10 54 W |
| M and J Air Incorporated Airport | Airport | 207 | Mercer | 41 12 45 N | 090 54 23 W |
| M D Borah Lake | Reservoir | 143 | Richland | 38 46 24 N | 088 04 12 W |
| M D Borah Lake Dam | Dam | 143 | Richland | 38 46 24 N | 088 04 12 W |
| M G T Channahon Illinois Heliport | Airport | 181 | Will | 41 26 56 N | 088 08 38 W |
| M L King Junior Elementary School | School | 225 | Champaign | 40 07 14 N | 088 13 21 W |
| M L King Junior Laboratory Experimental School | School | 181 | Cook | 42 02 35 N | 087 42 29 W |
| M Lester Flowers Park | Park | 186 | Cook | 42 00 19 N | 087 44 32 W |
| M Sheridan Magnet School | School | 182 | Cook | 41 50 39 N | 087 38 27 W |
| Mabel | Populated Place | 213 | Edgar | 39 52 35 N | 087 41 32 W |
| Mabel O'Donnell Elementary School | School | 219 | Kane | 41 47 08 N | 088 16 29 W |
| Maberry Cemetery | Cemetery | 189 | Greene | 39 15 06 N | 090 29 56 W |
| Mable Woolsey Elementary School | School | 233 | Knox | 40 54 06 N | 090 16 40 W |
| Mabry Landing Strip | Airport | 202 | Hancock | 40 18 30 N | 091 05 16 W |
| Mabry School (historical) | School | 133 | Wayne | 38 24 08 N | 088 33 51 W |
| Mac Daniels Beauty School | School | 183 | Cook | 41 58 40 N | 087 40 08 W |
| MacArthur Bridge | Bridge | 120 | St. Clair | 38 36 53 N | 090 11 05 W |
| MacArthur Elementary School | School | 239 | Cook | 42 03 35 N | 088 06 26 W |
| MacArthur Elementary School | School | 208 | McDonough | 40 26 50 N | 090 40 29 W |
| MacArthur High School | School | 212 | Macon | 39 51 13 N | 088 58 46 W |
| MacArthur Middle School | School | 205 | Cook | 42 06 33 N | 087 56 57 W |
| MacArthur School | School | 184 | Cook | 41 35 26 N | 087 35 59 W |
| MacArthur Woods Forest Preserve | Park | 199 | Lake | 42 15 02 N | 087 56 00 W |
| Macedonia | Populated Place | 163 | Franklin | 38 03 07 N | 088 42 19 W |
| Macedonia Baptist Church | Church | 181 | Cook | 41 55 36 N | 087 41 28 W |
| Macedonia Baptist Church | Church | 189 | Cumberland | 39 19 56 N | 088 01 41 W |
| Macedonia Baptist Church | Church | 151 | Marion | 38 31 54 N | 089 07 35 W |
| Macedonia Baptist Church | Church | 126 | St. Clair | 38 36 59 N | 090 09 04 W |
| Macedonia Baptist Church | Church | 200 | Whiteside | 41 47 55 N | 089 42 57 W |
| Macedonia Baptist Church | Church | 236 | Winnebago | 42 15 47 N | 089 07 12 W |
| Macedonia Cemetery | Cemetery | 189 | Cumberland | 39 19 54 N | 088 01 42 W |
| Macedonia Cemetery | Cemetery | 147 | Edwards | 38 31 07 N | 088 05 41 W |
| Macedonia Cemetery | Cemetery | 107 | Pope | 37 19 56 N | 088 38 32 W |
| Macedonia Church | Church | 208 | Douglas | 39 51 03 N | 088 24 24 W |
| Macedonia Church | Church | 186 | Fayette | 38 55 49 N | 088 50 57 W |
| Macedonia Church | Church | 146 | Massac | 37 13 09 N | 088 46 44 W |
| Macedonia Church | Church | 107 | Pope | 37 19 55 N | 088 38 33 W |
| Macedonia Church | Church | 104 | Pulaski | 37 08 23 N | 089 07 58 W |
| Macedonia Church | Church | 128 | Saline | 37 38 44 N | 088 32 10 W |
| Macedonia School | School | 234 | Jackson | 37 37 15 N | 089 23 51 W |
| Macedonia School (historical) | School | 174 | Fulton | 40 28 27 N | 089 59 32 W |
| Macedonia School (historical) | School | 122 | Saline | 37 38 25 N | 088 31 53 W |
| MacGovern School (historical) | School | 289 | McHenry | 42 13 32 N | 088 35 58 W |
| Machesney Airport (historical) | Airport | 224 | Winnebago | 42 21 00 N | 089 03 08 W |
| Machesney Mall Shopping Center | Locale | 223 | Winnebago | 42 21 01 N | 089 03 10 W |
| Machesney Park | Populated Place | 226 | Winnebago | 42 20 50 N | 089 02 20 W |
| Machesney Park Village Hall | Building | 223 | Winnebago | 42 20 52 N | 089 03 25 W |
| Machinery Building (historical) | Building | 178 | Cook | 41 46 36 N | 087 34 45 W |
| Machinery Hall | Building | 183 | Cook | 41 50 06 N | 087 37 45 W |
| Mack School | School | 241 | Winnebago | 42 26 46 N | 089 04 36 W |
| MacKee House (historical) | Building | 179 | Cook | 41 53 28 N | 087 37 42 W |
| Macker Cemetery | Cemetery | 145 | Calhoun | 38 52 38 N | 090 33 18 W |
| Mackey Cemetery | Cemetery | 163 | Clark | 39 21 40 N | 087 37 05 W |
| Mackey Cemetery | Cemetery | 192 | La Salle | 41 10 32 N | 088 52 11 W |