Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Cuba School | School | 169 | Madison | 38 41 49 N | 089 58 38 W |
| Cuba School (historical) | School | 126 | Franklin | 38 02 12 N | 088 49 01 W |
| Cuba School (historical) | School | 209 | Vermilion | 40 15 46 N | 087 39 58 W |
| Cuba Senior High School | School | 208 | Fulton | 40 29 37 N | 090 11 24 W |
| Cubbage Chapel | Church | 173 | Marion | 38 40 49 N | 089 00 03 W |
| Cubbage Chapel Cemetery | Cemetery | 173 | Marion | 38 40 49 N | 089 00 05 W |
| Cudahy Memorial Library | Building | 184 | Cook | 42 00 02 N | 087 39 35 W |
| Cudgetown Cemetery | Cemetery | 125 | Perry | 38 00 46 N | 089 19 15 W |
| Cudgetown School (historical) | School | 127 | Perry | 38 01 01 N | 089 19 16 W |
| Cuesport Billiard Academy | School | 208 | Peoria | 40 41 11 N | 089 41 01 W |
| Cuffe School | School | 184 | Cook | 41 44 30 N | 087 39 46 W |
| Cughan Cemetery | Cemetery | 128 | Lawrence | 38 45 28 N | 087 30 21 W |
| Culbertson Memorial Hospital | Hospital | 203 | Schuyler | 40 07 05 N | 090 33 52 W |
| Cullen School | School | 182 | Cook | 41 42 02 N | 087 36 41 W |
| Culli Cemetery | Cemetery | 140 | St. Clair | 38 25 23 N | 089 50 23 W |
| Cullom | Populated Place | 208 | Livingston | 40 52 40 N | 088 16 09 W |
| Cullom-Davis Library | Building | 183 | Peoria | 40 41 48 N | 089 37 00 W |
| Cullum Lake | Reservoir | 146 | Wayne | 38 24 23 N | 088 18 35 W |
| Culp School (historical) | School | 151 | Madison | 38 54 58 N | 090 05 51 W |
| Culton (historical) | Populated Place | 211 | La Salle | 41 29 03 N | 089 07 02 W |
| Culver | Populated Place | 184 | Menard | 40 00 24 N | 089 41 14 W |
| Culver Forest Preserve | Park | 207 | Kane | 41 46 16 N | 088 23 21 W |
| Culver Hall | Building | 180 | Cook | 41 47 27 N | 087 36 01 W |
| Culver Park | Park | 222 | Will | 41 37 20 N | 087 57 05 W |
| Cumberland | Populated Place | 194 | Clark | 39 18 14 N | 087 58 40 W |
| Cumberland Air Park | Airport | 192 | Cumberland | 39 18 50 N | 088 20 40 W |
| Cumberland Baptist Cemetery | Cemetery | 195 | Clark | 39 18 18 N | 087 58 57 W |
| Cumberland Baptist Church | Church | 201 | Cook | 42 03 59 N | 087 54 44 W |
| Cumberland Cemetery | Cemetery | 153 | Clark | 39 22 57 N | 087 36 48 W |
| Cumberland Cemetery | Cemetery | 206 | Henderson | 40 54 11 N | 090 52 34 W |
| Cumberland Cemetery | Cemetery | 197 | Marshall | 41 05 07 N | 089 08 50 W |
| Cumberland Church | Church | 131 | Massac | 37 13 15 N | 088 48 38 W |
| Cumberland Church | Church | 170 | Union | 37 31 23 N | 089 05 51 W |
| Cumberland County | Civil | 180 | Cumberland | 39 16 00 N | 088 15 02 W |
| Cumberland County Courthouse | Building | 183 | Cumberland | 39 16 22 N | 088 14 42 W |
| Cumberland County Farm (historical) | Locale | 178 | Cumberland | 39 18 09 N | 088 13 22 W |
| Cumberland Elementary School | School | 197 | Cook | 42 03 18 N | 087 54 21 W |
| Cumberland Elementary School | School | 182 | Cumberland | 39 15 27 N | 088 11 47 W |
| Cumberland High School | School | 182 | Cumberland | 39 15 27 N | 088 11 38 W |
| Cumberland Park | Park | 197 | Cook | 42 00 34 N | 087 50 07 W |
| Cumberland Presbyterian Cemetery | Cemetery | 204 | Henderson | 40 53 36 N | 090 52 00 W |
| Cumberland School (historical) | School | 171 | Fayette | 38 59 06 N | 088 58 34 W |
| Cumberland Sugar Creek Cemetery | Cemetery | 182 | Sangamon | 39 37 11 N | 089 41 04 W |
| Cumming Cemetery | Cemetery | 199 | Greene | 39 13 51 N | 090 31 42 W |
| Cummings Cemetery | Cemetery | 170 | Edgar | 39 29 07 N | 087 32 57 W |
| Cummings Life Science Center | Building | 180 | Cook | 41 47 23 N | 087 36 11 W |
| Cummings Living Center | Building | 250 | Winnebago | 42 16 17 N | 089 01 05 W |
| Cummings School (historical) | School | 279 | Boone | 42 22 39 N | 088 54 55 W |
| Cummings School (historical) | School | 236 | Knox | 41 04 39 N | 090 09 20 W |
| Cummings School (historical) | School | 180 | Sangamon | 39 44 06 N | 089 41 25 W |
| Cummings Square | Park | 193 | Cook | 41 53 22 N | 087 48 22 W |
| Cummins Cemetery | Cemetery | 202 | Alexander | 37 18 51 N | 089 20 52 W |
| Cummins Cemetery | Cemetery | 176 | Jasper | 38 56 10 N | 088 11 16 W |
| Cummins School (historical) | School | 165 | Jasper | 39 05 34 N | 088 04 50 W |
| Cummorn Post Office (historical) | Post Office | 181 | Cook | 41 45 03 N | 087 38 03 W |
| Cumnor Court Park | Park | 199 | Lake | 42 10 40 N | 087 50 12 W |
| Cundiff Cemetery | Cemetery | 125 | Williamson | 37 48 43 N | 089 06 56 W |
| Cuneo Hospital | Hospital | 180 | Cook | 41 57 44 N | 087 38 56 W |
| Cuneo Science Center | Building | 212 | Lake | 42 14 02 N | 087 49 56 W |
| Cunliff Park | Park | 189 | Cook | 42 03 53 N | 087 46 10 W |
| Cunningham Cemetery | Cemetery | 142 | Wabash | 38 32 38 N | 087 53 56 W |
| Cunningham Elementary School | School | 196 | Will | 41 32 28 N | 088 05 40 W |
| Cunningham Park | Park | 222 | Coles | 39 29 11 N | 088 22 08 W |
| Cunningham School (historical) | School | 202 | Bureau | 41 27 48 N | 089 43 23 W |
| Cunningham School (historical) | School | 217 | Vermilion | 40 26 43 N | 087 38 52 W |
| Cupps Cemetery | Cemetery | 204 | Clark | 39 28 25 N | 087 50 36 W |
| Curie Metropolitan High School | School | 183 | Cook | 41 48 09 N | 087 43 11 W |
| Curl Creek | Stream | | Adams | 39 55 51 N | 091 01 35 W |
| Curlee Cemetery | Cemetery | 155 | Perry | 38 10 41 N | 089 14 10 W |
| Curless Airport | Airport | 186 | Fulton | 40 15 46 N | 090 14 12 W |
| Curless Cemetery | Cemetery | 193 | Adams | 40 08 16 N | 091 11 29 W |
| Curran | Populated Place | 190 | Sangamon | 39 44 32 N | 089 46 19 W |
| Currens Hall | Building | 195 | McDonough | 40 28 14 N | 090 41 18 W |
| Currie School (historical) | School | 150 | Washington | 38 13 40 N | 089 10 12 W |
| Currier School (historical) | School | 240 | Stephenson | 42 18 56 N | 089 36 01 W |
| Curry Airport | Airport | 190 | Pike | 39 39 33 N | 090 42 00 W |
| Curry Cemetery | Cemetery | 136 | Wayne | 38 23 10 N | 088 21 32 W |
| Curry Chapel | Church | 177 | Schuyler | 40 06 50 N | 090 40 05 W |
| Curry Lake | Lake | 133 | Schuyler | 40 00 41 N | 090 28 08 W |
| Curry Park | Park | 183 | Cook | 42 02 31 N | 087 40 42 W |
| Curry School (historical) | School | 232 | Rock Island | 41 23 37 N | 090 38 43 W |
| Curtain School | School | 194 | Grundy | 41 09 08 N | 088 29 28 W |
| Curtis | Populated Place | 177 | Menard | 40 03 44 N | 089 47 25 W |
| Curtis Avenue Baptist Church | Church | 199 | Will | 41 32 47 N | 088 06 35 W |
| Curtis Cemetery | Cemetery | 158 | Massac | 37 19 41 N | 088 48 32 W |
| Curtis Creek | Stream | | Adams | 39 54 31 N | 091 25 16 W |
| Curtis Lake | Lake | 132 | Mason | 40 09 32 N | 090 11 54 W |
| Curtis School | School | 185 | Cook | 41 41 08 N | 087 37 17 W |
| Curtis School (historical) | School | 245 | Boone | 42 13 21 N | 088 44 51 W |
| Curtis School (historical) | School | 207 | Fulton | 40 36 43 N | 090 00 17 W |
| Curtis School (historical) | School | 201 | McDonough | 40 36 48 N | 090 26 46 W |
| Curtis School (historical) | School | 180 | Menard | 40 03 43 N | 089 47 59 W |
| Curtisville School (historical) | School | 140 | Edwards | 38 28 42 N | 088 05 40 W |
| Cusaac School (historical) | School | 202 | Shelby | 39 25 24 N | 088 47 47 W |
| Cushing Field Limited Airport | Airport | 194 | La Salle | 41 31 10 N | 088 36 20 W |
| Cushman | Populated Place | 205 | Moultrie | 39 39 36 N | 088 37 27 W |
| Cushman School (historical) | School | 141 | White | 38 05 00 N | 088 14 06 W |
| Custer | Populated Place | 210 | Marshall | 41 02 14 N | 089 09 13 W |
| Custer Park | Park | 239 | Knox | 40 55 55 N | 090 21 39 W |
| Custer Park | Park | 234 | Knox | 40 57 21 N | 090 20 59 W |
| Custer Park | Populated Place | 171 | Will | 41 14 43 N | 088 07 48 W |
| Custer Park Baptist Church | Church | 177 | Will | 41 15 40 N | 088 10 49 W |
| Custer Park Cemetery | Cemetery | 175 | Will | 41 14 30 N | 088 07 49 W |
| Custer Park Elementary School | School | 177 | Will | 41 14 27 N | 088 07 41 W |
| Cut Off Trail | Trail | 208 | McDonough | 40 27 27 N | 090 47 58 W |
| Cutler | Populated Place | 152 | Perry | 38 01 56 N | 089 33 56 W |
| Cutler Cemetery | Cemetery | 181 | Shelby | 39 24 05 N | 088 49 38 W |
| Cutler Election Precinct | Civil | 135 | Perry | 38 03 06 N | 089 32 55 W |
| Cutler Farm (historical) | Locale | 229 | Winnebago | 42 14 05 N | 089 06 25 W |
| Cutler School (historical) | School | 197 | Kendall | 41 40 20 N | 088 22 38 W |