Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Jacksonville Post Office | Post Office | 185 | Morgan | 39 44 06 N | 090 13 48 W |
| Jacksonville Public Library | Building | 184 | Morgan | 39 43 56 N | 090 13 48 W |
| Jacksonville School | School | 157 | Franklin | 38 06 44 N | 088 43 24 W |
| Jacksonville School (historical) | School | 171 | Pike | 39 26 36 N | 090 49 26 W |
| Jacob | Populated Place | 110 | Jackson | 37 44 42 N | 089 32 13 W |
| Jacob Chapel Cemetery | Cemetery | 143 | Wayne | 38 29 50 N | 088 39 03 W |
| Jacob Henry Mansion | Building | 168 | Will | 41 31 27 N | 088 04 27 W |
| Jacob Hunter Cemetery | Cemetery | 132 | Williamson | 37 47 45 N | 088 55 17 W |
| Jacob Park | Park | 178 | Cook | 41 57 59 N | 087 41 54 W |
| Jacobie School | Reservoir | 168 | Macoupin | 39 17 50 N | 090 05 28 W |
| Jacobs Camp | Locale | 116 | White | 38 10 32 N | 088 20 22 W |
| Jacobs Cemetery | Cemetery | 189 | Christian | 39 37 54 N | 089 03 03 W |
| Jacobs Cemetery | Cemetery | 136 | Edwards | 38 18 02 N | 088 00 53 W |
| Jacobs Chapel (historical) | Church | 143 | Wayne | 38 29 50 N | 088 39 03 W |
| Jacobs Healing Temple | Church | 183 | Cook | 41 47 15 N | 087 37 25 W |
| Jacobs Landing Strip | Airport | 122 | Monroe | 38 22 24 N | 090 19 17 W |
| Jacobs School (historical) | School | 222 | Livingston | 40 57 00 N | 088 22 40 W |
| Jacobs School (historical) | School | 104 | Pope | 37 10 28 N | 088 27 45 W |
| Jacobson Park | Park | 245 | McHenry | 42 23 08 N | 088 22 07 W |
| Jacques Building | Building | 179 | Cook | 41 53 32 N | 087 37 25 W |
| Jacques Marquette Monument | Park | 182 | Cook | 41 50 42 N | 087 41 57 W |
| Jahn Elementary School | School | 182 | Cook | 41 56 21 N | 087 40 31 W |
| Jake Creek | Stream | | Fulton | 40 17 12 N | 090 19 11 W |
| Jake Wolf Fish Hatchery | Locale | 152 | Mason | 40 25 45 N | 089 53 45 W |
| Jakes Branch | Stream | | Coles | 39 34 18 N | 088 04 00 W |
| Jalapa | Populated Place | 147 | Greene | 39 13 14 N | 090 19 27 W |
| Jamaat Al Muslimin | Church | 185 | Cook | 41 42 40 N | 087 38 35 W |
| Jamaica | Populated Place | 205 | Vermilion | 39 59 28 N | 087 48 24 W |
| Jamaica High School | School | 204 | Vermilion | 39 58 13 N | 087 49 22 W |
| James Break | Lake | 140 | Pike | 39 37 36 N | 091 13 16 W |
| James C Bush Elementary School | School | 229 | McHenry | 42 22 55 N | 088 14 22 W |
| James C Mitchell Park | Park | 202 | Lake | 42 10 10 N | 087 51 56 W |
| James C Petrillo Music Shell | Building | 181 | Cook | 41 52 44 N | 087 37 12 W |
| James Center Motivational Achievement | School | 167 | Madison | 38 54 32 N | 090 08 59 W |
| James Clayson Park | Park | 214 | DuPage | 41 58 51 N | 088 00 52 W |
| James Davis Cemetery | Cemetery | 183 | Cass | 39 56 03 N | 090 16 59 W |
| James Edward School | School | 225 | Will | 41 42 42 N | 088 02 49 W |
| James F Metcalf Student Experimental Theater | Building | 165 | Madison | 38 47 41 N | 090 00 05 W |
| James Foley Building | Building | 181 | Cook | 41 52 22 N | 087 39 25 W |
| James Hall Library | Building | 161 | Fayette | 38 57 56 N | 089 05 54 W |
| James Harper Grier Hall | Building | 226 | Warren | 40 54 51 N | 090 38 11 W |
| James Hart Junior High School | School | 192 | Cook | 41 33 31 N | 087 38 33 W |
| James Hean Family Cemetery | Cemetery | 139 | Edwards | 38 19 59 N | 088 01 06 W |
| James L Allen Center | Building | 176 | Cook | 42 03 23 N | 087 40 23 W |
| James M Adams Airport | Airport | 215 | Vermilion | 40 20 20 N | 087 34 15 W |
| James Madison School | School | 192 | Cook | 42 01 02 N | 087 51 38 W |
| James Memorial African Methodist Episcopal Church | Church | 191 | Cook | 41 52 46 N | 087 50 24 W |
| James Park | Park | 185 | Cook | 42 01 26 N | 087 42 12 W |
| James Park | Park | 154 | Tazewell | 40 34 02 N | 089 38 24 W |
| James Rankin House | Building | 180 | Cook | 41 47 30 N | 087 35 46 W |
| James School (historical) | School | 213 | Whiteside | 41 51 04 N | 089 54 40 W |
| James W Andrew Airport | Airport | 200 | Macoupin | 39 24 52 N | 090 01 19 W |
| James W Shelton Senior School | School | 183 | Cook | 41 48 31 N | 087 37 01 W |
| James Wadsworth Child - Parent Center | School | 181 | Cook | 41 46 42 N | 087 35 19 W |
| James Ward Elementary School | School | 182 | Cook | 41 50 36 N | 087 38 06 W |
| James Weldon Johnson School (historical) | School | 126 | St. Clair | 38 36 57 N | 090 08 55 W |
| Jamesburg | Populated Place | 208 | Vermilion | 40 15 44 N | 087 44 56 W |
| Jamestown | Populated Place | 155 | Clinton | 38 44 02 N | 089 30 52 W |
| Jamestown | Populated Place | 140 | Perry | 38 02 59 N | 089 31 45 W |
| Jamestown (historical) | Populated Place | 134 | Hamilton | 38 02 20 N | 088 22 27 W |
| Jamestown Cemetery | Cemetery | 152 | Clinton | 38 44 06 N | 089 30 42 W |
| Jamestown Park | Park | 225 | Winnebago | 42 13 22 N | 089 03 55 W |
| Jamesway Park | Park | 257 | McHenry | 42 12 58 N | 088 14 37 W |
| Jamie McGee Elementary School | School | 207 | Will | 41 41 58 N | 088 06 50 W |
| Jamieson Community Center | Building | 236 | Warren | 40 54 05 N | 090 38 42 W |
| Jamieson Elementary School | School | 181 | Cook | 41 59 03 N | 087 42 03 W |
| Jamison Creek | Stream | | Marion | 38 37 35 N | 088 44 35 W |
| Jamison School (historical) | School | 246 | Bureau | 41 14 55 N | 089 36 26 W |
| Jane Adams Junior High School | School | 249 | Cook | 42 00 47 N | 088 07 13 W |
| Jane Adams School (historical) | School | 206 | Rock Island | 41 28 32 N | 090 27 41 W |
| Jane Addams Elementary School | School | 222 | Cook | 42 07 26 N | 088 01 07 W |
| Jane Addams Elementary School | School | 179 | Cook | 41 41 55 N | 087 31 59 W |
| Jane Addams Elementary School | School | 178 | Sangamon | 39 48 49 N | 089 41 05 W |
| Jane Addams Homes (subdivision) | Populated Place | 181 | Cook | 41 52 10 N | 087 39 35 W |
| Jane Addams Middle School | School | 205 | Will | 41 41 17 N | 088 06 26 W |
| Jane Addams School | School | 192 | Cook | 41 54 01 N | 087 50 44 W |
| Jane Hall | Building | 180 | Morgan | 39 43 54 N | 090 13 29 W |
| Jane Stenson Elementary School | School | 191 | Cook | 42 02 55 N | 087 45 31 W |
| Janesville | Populated Place | 210 | Cumberland | 39 22 27 N | 088 14 37 W |
| Janesville Cemetery | Cemetery | 216 | Coles | 39 22 47 N | 088 14 58 W |
| Janesville Post Office | Post Office | 210 | Cumberland | 39 22 28 N | 088 14 42 W |
| Janme Addams Hull House | Building | 181 | Cook | 41 52 18 N | 087 38 51 W |
| Janssen Airport | Airport | 266 | Stephenson | 42 13 41 N | 089 44 17 W |
| Janssen Airport | Airport | 221 | Woodford | 40 51 56 N | 089 00 12 W |
| Janssen Hall | Building | 186 | Bond | 38 53 37 N | 089 24 34 W |
| Janura Park | Park | 187 | Cook | 41 50 20 N | 087 47 24 W |
| Janusick Airport | Airport | 204 | La Salle | 41 07 45 N | 089 06 25 W |
| Jaques | Populated Place | 157 | Brown | 39 53 02 N | 090 44 35 W |
| Jarman Memorial Hospital | Hospital | 200 | Douglas | 39 48 19 N | 088 17 17 W |
| Jarrett Prairie Nature Preserve | Park | 232 | Ogle | 42 06 37 N | 089 16 04 W |
| Jarvis Avenue Park | Park | 181 | Cook | 42 01 08 N | 087 39 51 W |
| Jarvis School (historical) | School | 191 | Iroquois | 40 53 23 N | 087 43 52 W |
| Jason and Broadus Cemetery | Cemetery | 205 | Marshall | 41 01 23 N | 089 22 27 W |
| Jasper County | Civil | 160 | Jasper | 39 00 02 N | 088 10 00 W |
| Jasper County Flying Club Airport | Airport | 168 | Jasper | 38 55 54 N | 088 09 25 W |
| Jasper County Safety Council Heliport | Airport | 163 | Jasper | 38 59 22 N | 088 10 35 W |
| Jasper County State Prairie Chicken Sanctuary | Park | 165 | Jasper | 38 56 47 N | 088 15 14 W |
| Jasper Elementary School | School | 148 | Wayne | 38 24 02 N | 088 19 35 W |
| Jasper Park | Park | 201 | Macon | 39 50 41 N | 088 56 26 W |
| Java School (historical) | School | 254 | McHenry | 42 10 06 N | 088 38 14 W |
| Jay Cee Park | Park | 244 | Cook | 42 00 29 N | 088 06 46 W |
| Jay Schertz Farm Airport | Airport | 237 | Woodford | 40 50 30 N | 089 16 28 W |
| Jay Stream Middle School | School | 229 | DuPage | 41 54 58 N | 088 07 42 W |
| Jaycee Memorial Park | Park | 201 | Lake | 42 10 20 N | 087 52 06 W |
| Jaycee Park | Park | 174 | Bond | 38 53 44 N | 089 23 49 W |
| Jaycee Park | Park | 185 | Christian | 39 31 40 N | 089 15 13 W |
| Jaycee Park | Park | 195 | Cook | 42 01 37 N | 087 53 11 W |
| Jaycee Park | Park | 202 | Cook | 42 05 34 N | 087 56 04 W |
| Jaycee Park | Park | 184 | Cook | 41 32 44 N | 087 32 22 W |
| Jaycee Park | Park | 200 | Cook | 41 59 28 N | 087 49 34 W |