Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Carver Primary School | School | 179 | Cook | 41 39 11 N | 087 36 03 W |
| Carver Recreational Center | Park | 157 | Peoria | 40 41 27 N | 089 36 21 W |
| Carver School (historical) | School | 128 | St. Clair | 38 38 17 N | 090 08 44 W |
| Carville (subdivision) | Populated Place | 181 | Cook | 41 50 45 N | 087 37 02 W |
| Cary | Populated Place | 251 | McHenry | 42 12 43 N | 088 14 17 W |
| Cary Branch | Stream | | Shelby | 39 13 52 N | 088 46 24 W |
| Cary Cemetery | Cemetery | 250 | McHenry | 42 12 37 N | 088 14 15 W |
| Cary Commons Shopping Center | Locale | 261 | McHenry | 42 13 12 N | 088 15 36 W |
| Cary Country Club | Locale | 226 | McHenry | 42 11 37 N | 088 14 43 W |
| Cary Creek | Stream | | McHenry | 42 11 48 N | 088 14 03 W |
| Cary Fire Department Heliport | Airport | 253 | Henry | 42 12 45 N | 088 15 08 W |
| Cary Junior High Prairie Nature Preserve | Park | 257 | McHenry | 42 12 50 N | 088 13 56 W |
| Cary Junior High School | School | 263 | McHenry | 42 12 54 N | 088 13 55 W |
| Cary Square Shopping Center | Locale | 260 | McHenry | 42 13 07 N | 088 15 20 W |
| Cary United Methodist Church | Church | 259 | McHenry | 42 12 55 N | 088 14 13 W |
| Cary Village Hall | Building | 265 | McHenry | 42 12 16 N | 088 15 15 W |
| Cary-Grove Community High School | School | 259 | McHenry | 42 13 17 N | 088 14 30 W |
| Cary-Grove Evangelical Free Church | Church | 259 | McHenry | 42 12 24 N | 088 14 55 W |
| Casa De Aero Park | Airport | 260 | Kane | 42 08 55 N | 088 33 35 W |
| Cascade | Populated Place | 175 | Sangamon | 39 40 13 N | 089 29 31 W |
| Cascade School (historical) | School | 176 | Sangamon | 39 41 04 N | 089 29 33 W |
| Case Creek | Stream | | Rock Island | 41 27 30 N | 090 31 57 W |
| Case School (historical) | School | 186 | Kankakee | 41 03 18 N | 087 49 46 W |
| Case School (historical) | School | 166 | Madison | 38 49 04 N | 089 43 34 W |
| Case-Halstead Public Library | Building | 139 | Clinton | 38 36 37 N | 089 21 53 W |
| Casey | Populated Place | 197 | Clark | 39 17 57 N | 087 59 33 W |
| Casey Avenue Baptist Church | Church | 137 | Jefferson | 38 18 53 N | 088 53 22 W |
| Casey Cemetery | Cemetery | 192 | Fayette | 39 10 22 N | 089 09 37 W |
| Casey Cemetery | Cemetery | 202 | Montgomery | 39 09 40 N | 089 16 14 W |
| Casey Church of Christ | Church | 195 | Clark | 39 18 22 N | 087 58 21 W |
| Casey City Building | Building | 197 | Clark | 39 18 00 N | 087 59 28 W |
| Casey City Cemetery | Cemetery | 193 | Clark | 39 17 52 N | 087 58 48 W |
| Casey Country Club | Locale | 195 | Clark | 39 18 30 N | 087 58 57 W |
| Casey Cumberland Presbyterian Church | Church | 198 | Clark | 39 18 00 N | 087 59 33 W |
| Casey Ditch | Canal | 125 | Jefferson | 38 13 49 N | 088 54 37 W |
| Casey First Church of the Nazarene | Church | 199 | Clark | 39 18 10 N | 087 59 39 W |
| Casey Fork | Stream | | Franklin | 38 05 27 N | 088 57 24 W |
| Casey Fork Subimpoundment Dam | Dam | 123 | Jefferson | 38 11 15 N | 088 55 50 W |
| Casey Junior High School | School | 162 | Jefferson | 38 18 56 N | 088 54 46 W |
| Casey Municipal Airport | Airport | 199 | Clark | 39 18 08 N | 088 00 14 W |
| Casey School (historical) | School | 209 | Champaign | 39 58 57 N | 088 26 37 W |
| Casey Spring | Spring | 135 | Johnson | 37 26 43 N | 088 50 29 W |
| Casey Spring Church | Church | 141 | Johnson | 37 26 46 N | 088 50 33 W |
| Casey Township Library | Building | 196 | Clark | 39 18 01 N | 087 59 20 W |
| Casey-Westfield High School | School | 197 | Clark | 39 18 18 N | 087 59 18 W |
| Caseyville | Populated Place | 137 | St. Clair | 38 38 12 N | 090 01 32 W |
| Caseyville Elementary School | School | 129 | St. Clair | 38 38 11 N | 090 01 50 W |
| Cash Creek | Stream | | Mercer | 41 14 46 N | 090 51 03 W |
| Cash Island | Island | 137 | Pike | 39 25 13 N | 090 58 17 W |
| Cash School (historical) | School | 300 | McHenry | 42 25 46 N | 088 34 28 W |
| Cashman School (historical) | School | 232 | Knox | 40 47 16 N | 090 20 54 W |
| Cashmere School (historical) | School | 188 | Livingston | 41 00 12 N | 088 45 31 W |
| Casner | Populated Place | 215 | Macon | 39 48 01 N | 088 47 28 W |
| Casner School (historical) | School | 156 | Jefferson | 38 20 00 N | 089 07 37 W |
| Caspars | Populated Place | 140 | Washington | 38 18 00 N | 089 39 42 W |
| Caspars Post Office (historical) | Post Office | 140 | Washington | 38 18 00 N | 089 39 42 W |
| Casper Church | Church | 190 | Union | 37 29 26 N | 089 15 13 W |
| Casper-Stolle Quarry | Mine | 137 | St. Clair | 38 32 32 N | 090 09 51 W |
| Cass (historical) | Populated Place | 181 | Cass | 39 58 05 N | 090 16 09 W |
| Cass Cemetery | Cemetery | 213 | DuPage | 41 43 47 N | 087 58 49 W |
| Cass Cemetery | Cemetery | 194 | Montgomery | 39 16 24 N | 089 34 06 W |
| Cass Cemetery | Cemetery | 192 | Sangamon | 39 54 23 N | 089 26 59 W |
| Cass County | Civil | 178 | Cass | 39 57 00 N | 090 14 00 W |
| Cass County Courthouse | Building | 189 | Cass | 39 57 02 N | 090 12 38 W |
| Cass Junior High School | School | 222 | DuPage | 41 43 59 N | 087 58 42 W |
| Cassady Cemetery | Cemetery | 215 | Edgar | 39 33 56 N | 087 42 54 W |
| Cassar Creek | Stream | | Fayette | 38 50 42 N | 089 09 38 W |
| Cassell Creek | Stream | | Coles | 39 29 14 N | 088 12 31 W |
| Cassell Elementary School | School | 189 | Cook | 41 41 15 N | 087 42 14 W |
| Cassem School (historical) | School | 186 | Grundy | 41 25 42 N | 088 30 35 W |
| Cast Airport | Airport | 204 | Vermilion | 40 02 20 N | 087 46 54 W |
| Casteen Cemetery | Cemetery | 193 | Brown | 39 53 42 N | 090 40 33 W |
| Caster Hall | Building | 250 | Winnebago | 42 16 14 N | 089 01 01 W |
| Castle Fin | Populated Place | 194 | Clark | 39 28 12 N | 087 44 00 W |
| Castle Junction | Populated Place | 230 | Rock Island | 41 23 33 N | 090 34 40 W |
| Castle School (historical) | School | 171 | Crawford | 38 52 08 N | 087 44 28 W |
| Castleton | Populated Place | 240 | Stark | 41 07 04 N | 089 42 22 W |
| Castleton Post Office | Post Office | 240 | Stark | 41 07 03 N | 089 42 24 W |
| Castor Post Office (historical) | Post Office | 127 | Wayne | 38 23 10 N | 088 31 16 W |
| Cate Family Cemetery | Cemetery | 201 | Adams | 40 03 51 N | 091 09 03 W |
| Caterpillar Aurora Heliport | Airport | 201 | Kendall | 41 43 01 N | 088 21 33 W |
| Cates Cemetery | Cemetery | 142 | Wayne | 38 30 15 N | 088 30 06 W |
| Cates School (historical) | School | 160 | Hamilton | 38 11 53 N | 088 39 09 W |
| Catfish (historical) | Populated Place | 201 | Edgar | 39 40 18 N | 087 55 40 W |
| Catfish Bend | Bend | 121 | Wabash | 38 30 20 N | 087 39 02 W |
| Catfish Cemetery | Cemetery | 200 | Edgar | 39 40 22 N | 087 55 44 W |
| Catfish Corner Picnic Area | Locale | 134 | Hamilton | 38 03 23 N | 088 24 11 W |
| Catfish Cove Picnic Area | Locale | 227 | Lake | 42 26 48 N | 088 10 57 W |
| Catfish Creek | Stream | | Edgar | 39 40 50 N | 087 56 01 W |
| Catfish Point Cemetery | Cemetery | 203 | Edgar | 39 39 31 N | 087 53 05 W |
| Catfish School (historical) | School | 196 | Edgar | 39 40 21 N | 087 55 37 W |
| Catharine | Populated Place | 196 | La Salle | 41 31 23 N | 088 43 09 W |
| Cathedral Baptist Church | Church | 259 | Winnebago | 42 11 52 N | 089 01 40 W |
| Cathedral Baptist School | School | 254 | Winnebago | 42 11 58 N | 089 01 55 W |
| Cathedral Missionary Baptist Church | Church | 183 | Cook | 41 48 24 N | 087 37 26 W |
| Cathedral of Joy Baptist Church | Church | 210 | Cook | 41 32 34 N | 087 41 39 W |
| Cathedral of Love Missionary Baptist Church | Church | 179 | Cook | 41 45 31 N | 087 36 57 W |
| Cathedral of Saint James | Church | 179 | Cook | 41 53 40 N | 087 37 35 W |
| Cathedral of Saint Raymonds | Church | 198 | Will | 41 32 07 N | 088 06 02 W |
| Cathedral of Worship Church | Church | 197 | Adams | 39 56 02 N | 091 22 33 W |
| Cathedral School | School | 180 | Cook | 41 53 47 N | 087 37 40 W |
| Cathedral Temple of Divine Love | Church | 182 | Cook | 41 45 36 N | 087 37 59 W |
| Cather Elementary School | School | 182 | Cook | 41 52 49 N | 087 41 58 W |
| Cather Elementary School | School | 182 | Cook | 41 52 56 N | 087 42 07 W |
| Catherine College | School | 178 | Cook | 41 53 06 N | 087 37 23 W |
| Catholic Cemetery | Cemetery | 254 | Bureau | 41 17 29 N | 089 35 14 W |
| Catholic Cemetery | Cemetery | 144 | Edwards | 38 15 44 N | 088 00 48 W |
| Catholic Cemetery | Cemetery | 211 | Hancock | 40 21 21 N | 091 24 32 W |
| Catholic Cemetery | Cemetery | 192 | Johnson | 37 34 13 N | 088 46 40 W |
| Catholic North Cemetery | Cemetery | 165 | Grundy | 41 23 24 N | 088 24 51 W |