Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Greenwood Lake | Reservoir | 215 | Champaign | 40 20 46 N | 088 18 08 W |
| Greenwood Lake Dam | Dam | 218 | Champaign | 40 20 30 N | 088 18 00 W |
| Greenwood Manor Nursing Home | Hospital | 198 | Jersey | 39 06 43 N | 090 19 42 W |
| Greenwood Park | Park | 194 | Macon | 39 50 09 N | 088 57 27 W |
| Greenwood School | School | 213 | Coles | 39 28 49 N | 088 10 21 W |
| Greenwood School | School | 195 | Cook | 41 40 03 N | 087 41 15 W |
| Greenwood School (historical) | School | 213 | Adams | 39 51 20 N | 090 56 11 W |
| Greenwood School (historical) | School | 174 | Christian | 39 37 35 N | 089 25 33 W |
| Greenwood School (historical) | School | 221 | Coles | 39 30 11 N | 087 59 12 W |
| Greenwood School (historical) | School | 200 | Douglas | 39 42 13 N | 088 01 34 W |
| Greenwood School (historical) | School | 156 | Jasper | 38 53 32 N | 088 07 56 W |
| Greenwood Slough | Gut | 168 | Rock Island | 41 27 40 N | 090 26 28 W |
| Greer | Populated Place | 229 | Iroquois | 40 31 59 N | 087 35 41 W |
| Greer Cemetery | Cemetery | 119 | Jackson | 37 53 19 N | 089 13 15 W |
| Greer Park | Park | 155 | Fayette | 38 58 22 N | 089 06 14 W |
| Greer School (historical) | School | 180 | Christian | 39 38 00 N | 089 27 06 W |
| Greer School (historical) | School | 123 | Gallatin | 37 39 55 N | 088 19 07 W |
| Greeves Cemetery | Cemetery | 201 | Marshall | 41 01 26 N | 089 22 24 W |
| Gregg Hall | Building | 212 | Coles | 39 28 48 N | 088 10 34 W |
| Gregg Memorial African Methodist Episcopal Church | Church | 183 | Cook | 41 47 14 N | 087 38 39 W |
| Gregory Branch | Stream | | Wayne | 38 22 38 N | 088 39 45 W |
| Gregory Cemetery | Cemetery | 189 | Pope | 37 21 17 N | 088 32 20 W |
| Gregory Church | Church | 226 | McLean | 40 38 57 N | 088 54 57 W |
| Gregory Elementary School | School | 183 | Cook | 41 52 14 N | 087 43 06 W |
| Gregory Elementary School | School | 265 | Winnebago | 42 15 32 N | 089 00 53 W |
| Gregory Hall | Building | 225 | Champaign | 40 06 20 N | 088 13 41 W |
| Gregory Hall | Building | 208 | Lake | 42 14 45 N | 087 49 47 W |
| Gregory Park | Park | 204 | Cook | 42 04 31 N | 087 55 51 W |
| Gregory Park | Park | 189 | Kane | 41 46 55 N | 088 18 45 W |
| Gregory School | School | 228 | Champaign | 40 07 17 N | 088 14 43 W |
| Gregory School | School | 202 | Cook | 42 04 27 N | 087 55 53 W |
| Gregory School | School | 124 | Union | 37 32 07 N | 089 20 23 W |
| Gregory School (historical) | School | 167 | Greene | 39 25 10 N | 090 24 28 W |
| Gregory School (historical) | School | 282 | McHenry | 42 16 58 N | 088 24 29 W |
| Gregory School (historical) | School | 223 | McLean | 40 40 35 N | 088 54 04 W |
| Grennan Heights Park | Park | 196 | Cook | 42 01 50 N | 087 48 39 W |
| Greogory Middle School | School | 206 | Will | 41 42 52 N | 088 10 39 W |
| Gresham Cemetery | Cemetery | 203 | Calhoun | 39 13 29 N | 090 41 38 W |
| Gresham Hollow | Valley | | Calhoun | 39 13 04 N | 090 42 57 W |
| Gresham School | School | 183 | Cook | 41 44 22 N | 087 38 42 W |
| Gretna | Populated Place | 241 | DuPage | 41 53 53 N | 088 06 05 W |
| Greve Cemetery | Cemetery | 254 | Cook | 42 03 25 N | 088 07 37 W |
| Grewe Lake | Lake | 122 | Washington | 38 28 34 N | 089 34 54 W |
| Grey Park | Park | 187 | Cook | 42 02 03 N | 087 41 10 W |
| Greystone Golf Course | Locale | 213 | Will | 41 32 44 N | 087 48 11 W |
| Gridley | Populated Place | 230 | McLean | 40 44 36 N | 088 52 53 W |
| Gridley Cemetery | Cemetery | 226 | Lake | 42 12 46 N | 087 59 46 W |
| Gridley Cemetery | Cemetery | 234 | McLean | 40 45 10 N | 088 52 20 W |
| Gridley Elementary School | School | 229 | McLean | 40 44 37 N | 088 53 08 W |
| Gridley High School | School | 228 | McLean | 40 44 34 N | 088 53 07 W |
| Gridley Junior High School | School | 229 | McLean | 40 44 38 N | 088 53 07 W |
| Gridley School (historical) | School | 214 | Lake | 42 12 22 N | 087 59 09 W |
| Gridley School (historical) | School | 228 | Whiteside | 41 51 01 N | 090 00 20 W |
| Grieb Cemetery | Cemetery | 150 | Union | 37 25 14 N | 089 16 10 W |
| Grieder School (historical) | School | 182 | Effingham | 38 56 34 N | 088 46 41 W |
| Grier School (historical) | School | 220 | Warren | 40 54 40 N | 090 36 46 W |
| Griesemer Cemetery | Cemetery | 195 | Tazewell | 40 25 43 N | 089 25 05 W |
| Griffin | Populated Place | 209 | Mercer | 41 14 25 N | 090 29 22 W |
| Griffin (historical) | Populated Place | 179 | Clark | 39 26 48 N | 087 39 17 W |
| Griffin Cemetery | Cemetery | 210 | Pope | 37 31 46 N | 088 38 50 W |
| Griffin Cemetery | Cemetery | 129 | St. Clair | 38 31 54 N | 089 49 58 W |
| Griffin High School | School | 181 | Sangamon | 39 48 08 N | 089 40 52 W |
| Griffin School (historical) | School | 238 | Henry | 41 18 59 N | 090 13 56 W |
| Griffith Cemetery | Cemetery | 221 | De Witt | 40 11 45 N | 088 51 13 W |
| Griffith Cemetery | Cemetery | 174 | Fayette | 38 58 37 N | 088 58 42 W |
| Griffith Cemetery | Cemetery | 183 | Hardin | 37 32 39 N | 088 13 53 W |
| Griffith Cemetery | Cemetery | 208 | Mercer | 41 12 32 N | 090 50 40 W |
| Griffith Creek | Stream | | Sangamon | 39 48 19 N | 089 26 14 W |
| Griffith Farms Lake | Reservoir | 134 | White | 38 05 06 N | 088 12 48 W |
| Griffith Farms Lake Dam | Dam | 134 | White | 38 05 06 N | 088 12 48 W |
| Griffith Lake | Lake | 118 | White | 38 05 08 N | 088 10 38 W |
| Griffith RLA Airport | Airport | 164 | Sangamon | 39 48 35 N | 089 44 40 W |
| Grigg | Populated Place | 129 | Randolph | 38 11 26 N | 089 54 28 W |
| Griggs Chapel (historical) | Church | 135 | Cass | 40 02 44 N | 090 20 55 W |
| Griggs School (historical) | School | 186 | Bond | 38 59 21 N | 089 19 10 W |
| Griggs School (historical) | School | 305 | Kane | 41 59 45 N | 088 28 39 W |
| Griggs School (historical) | School | 190 | Peoria | 40 36 34 N | 089 52 12 W |
| Griggs School (historical) | School | 192 | Sangamon | 39 32 18 N | 089 37 40 W |
| Griggsville | Populated Place | 215 | Pike | 39 42 32 N | 090 43 28 W |
| Griggsville Cemetery | Cemetery | 205 | Pike | 39 42 50 N | 090 43 57 W |
| Griggsville High School | School | 214 | Pike | 39 42 37 N | 090 43 27 W |
| Griggsville Historic District | Park | 217 | Pike | 39 42 30 N | 090 43 30 W |
| Griggsville Landing | Locale | 133 | Pike | 39 41 49 N | 090 38 51 W |
| Grigsby Lake | Reservoir | 155 | Madison | 38 49 42 N | 089 51 06 W |
| Grigsby Lake Dam | Dam | 155 | Madison | 38 49 42 N | 089 51 06 W |
| Grigsby Middle School | School | 128 | Madison | 38 43 47 N | 090 05 02 W |
| Grimes Addition | Populated Place | 196 | Whiteside | 41 47 53 N | 089 44 55 W |
| Grimes Cemetery | Cemetery | 192 | Jersey | 39 06 56 N | 090 24 09 W |
| Grimes Island | Island | 135 | Calhoun | 39 18 08 N | 090 47 05 W |
| Grimes School | School | 187 | Cook | 41 46 32 N | 087 45 31 W |
| Grimes School (historical) | School | 260 | Lee | 41 49 07 N | 089 00 50 W |
| Grimes School (historical) | School | 198 | Macoupin | 39 09 28 N | 089 50 50 W |
| Grimes School (historical) | School | 187 | Pike | 39 49 31 N | 090 45 43 W |
| Grimm School (historical) | School | 209 | Coles | 39 31 43 N | 088 03 08 W |
| Grimmett School (historical) | School | 199 | Macoupin | 39 26 36 N | 089 56 24 W |
| Grimsby | Populated Place | 110 | Jackson | 37 45 01 N | 089 26 57 W |
| Grindstaff Hollow | Valley | | Gallatin | 37 37 24 N | 088 19 19 W |
| Grindstaff Hollow Club Dam | Dam | 124 | Gallatin | 37 37 12 N | 088 19 30 W |
| Grindstaff Hollow Club Lake | Reservoir | 124 | Gallatin | 37 37 12 N | 088 19 30 W |
| Grindstone Creek | Stream | | Adams | 39 53 00 N | 090 58 44 W |
| Grindstone Creek | Stream | | Adams | 40 08 35 N | 091 19 19 W |
| Grindstone Creek | Stream | | McDonough | 40 17 37 N | 090 46 45 W |
| Grindstone Creek | Stream | | White | 38 01 06 N | 088 12 04 W |
| Grinnel Slough | Gut | 105 | Gallatin | 37 52 24 N | 088 05 58 W |
| Grinnell | Populated Place | 123 | Massac | 37 16 45 N | 088 52 20 W |
| Grinnell School (historical) | School | 196 | Kankakee | 41 08 00 N | 087 49 19 W |
| Grisby Cemetery | Cemetery | 265 | Stephenson | 42 22 18 N | 089 45 35 W |
| Grisham School (historical) | School | 202 | Pope | 37 25 15 N | 088 35 30 W |
| Grisold (historical) | Populated Place | 132 | Lawrence | 38 42 55 N | 087 41 15 W |
| Grissinger School (historical) | School | 269 | Carroll | 42 05 39 N | 089 48 09 W |