Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Concord School (historical) | School | 134 | Hamilton | 38 05 40 N | 088 27 29 W |
| Concord School (historical) | School | 218 | Peoria | 40 38 25 N | 089 58 04 W |
| Concord School (historical) | School | 143 | Pulaski | 37 12 30 N | 089 07 01 W |
| Concord School (historical) | School | 174 | Randolph | 38 04 04 N | 089 41 14 W |
| Concord School (historical) | School | 144 | Wayne | 38 29 26 N | 088 38 27 W |
| Concord School (historical) | School | 159 | Williamson | 37 47 26 N | 088 48 01 W |
| Concord Square Park | Park | 227 | DuPage | 41 45 52 N | 088 01 27 W |
| Concord Townhall | Building | 229 | Adams | 39 59 20 N | 090 58 34 W |
| Concord United Methodist Church | Church | 180 | Morgan | 39 49 00 N | 090 22 10 W |
| Concordia Cemetery | Cemetery | 190 | Cook | 41 52 37 N | 087 49 30 W |
| Concordia Cemetery | Cemetery | 204 | Kankakee | 41 03 19 N | 087 40 31 W |
| Concordia Cemetery | Cemetery | 162 | St. Clair | 38 29 57 N | 090 05 43 W |
| Concordia Church | Church | 167 | St. Clair | 38 29 58 N | 090 05 45 W |
| Concordia Evangelical Lutheran Church | Church | 180 | Cook | 41 56 20 N | 087 41 42 W |
| Concordia Evangelical Lutheran Church | Church | 198 | Henry | 41 27 01 N | 090 09 12 W |
| Concordia Evangelical Lutheran Church | Church | 128 | Madison | 38 42 19 N | 090 08 29 W |
| Concordia Lutheran Church | Church | 196 | Clark | 39 22 42 N | 087 41 40 W |
| Concordia Lutheran Church | Church | 182 | Cook | 41 57 07 N | 087 40 46 W |
| Concordia Lutheran Church | Church | 187 | Cook | 41 37 23 N | 087 42 44 W |
| Concordia Lutheran Church | Church | 186 | Cook | 41 50 03 N | 087 47 53 W |
| Concordia Lutheran Church | Church | 204 | Macon | 39 49 07 N | 088 54 15 W |
| Concordia Lutheran Church | Church | 223 | Winnebago | 42 19 59 N | 089 03 22 W |
| Concordia Lutheran School | School | 211 | Peoria | 40 44 48 N | 089 37 21 W |
| Concordia School | School | 181 | Cook | 41 56 19 N | 087 41 41 W |
| Concordia Seminary | School | 186 | Sangamon | 39 48 34 N | 089 38 19 W |
| Concordia University | School | 192 | Cook | 41 53 56 N | 087 48 35 W |
| Condell Memorial Hospital | Hospital | 219 | Lake | 42 16 29 N | 087 57 25 W |
| Condell Memorial Hospital Heliport | Airport | 220 | Lake | 42 16 30 N | 087 57 25 W |
| Condon School (historical) | School | 210 | Bureau | 41 25 12 N | 089 41 38 W |
| Condra School (historical) | School | 241 | Knox | 41 02 29 N | 090 22 27 W |
| Confederate Cemetery | Cemetery | 180 | Madison | 38 55 03 N | 090 11 43 W |
| Confederate Cemetery | Cemetery | 178 | Rock Island | 41 31 03 N | 090 32 02 W |
| Confidence | Populated Place | 174 | Fayette | 38 55 22 N | 088 55 35 W |
| Confidence Station (historical) | School | 155 | Madison | 38 41 00 N | 089 57 02 W |
| Congerville | Populated Place | 228 | Woodford | 40 37 01 N | 089 12 15 W |
| Congerville Church | Church | 196 | Woodford | 40 37 17 N | 089 14 21 W |
| Congerville Elementary School | School | 227 | Woodford | 40 37 03 N | 089 12 01 W |
| Congregation A G Beth Israel | Church | 182 | Cook | 41 59 49 N | 087 43 15 W |
| Congregation Am Echod | Church | 216 | Cook | 41 29 31 N | 087 41 24 W |
| Congregation Anshe Roumania (historical) | Church | 182 | Cook | 41 51 48 N | 087 42 58 W |
| Congregation B'nai Maccabim | Church | 213 | Lake | 42 11 01 N | 087 48 05 W |
| Congregation B'nai Tikvah | Church | 204 | Lake | 42 10 02 N | 087 52 00 W |
| Congregation Bene Shalom | Church | 185 | Cook | 42 01 34 N | 087 44 23 W |
| Congregation Beth Judea | Church | 215 | Lake | 42 11 27 N | 087 59 18 W |
| Congregation Beth Or | Church | 206 | Lake | 42 09 57 N | 087 52 37 W |
| Congregation Beth Shalom | Church | 210 | Cook | 42 07 37 N | 087 51 49 W |
| Congregation Bnai Emunah | Church | 192 | Cook | 42 02 50 N | 087 44 35 W |
| Congregation Kins of West Rogers Park | Church | 181 | Cook | 42 00 12 N | 087 42 02 W |
| Congregation Kol Emeth | Church | 187 | Cook | 42 00 44 N | 087 45 23 W |
| Congregation of Israel | Church | 183 | Cook | 41 47 39 N | 087 37 22 W |
| Congregation Or Shalom | Church | 211 | Lake | 42 14 33 N | 087 57 59 W |
| Congregation Rodfei-Zedek | Church | 180 | Cook | 41 48 03 N | 087 35 06 W |
| Congregation Solel | Church | 193 | Lake | 42 09 38 N | 087 48 04 W |
| Congregation Solel Library | Building | 193 | Lake | 42 09 38 N | 087 48 04 W |
| Congregation Yehuda Moshe | Church | 186 | Cook | 42 00 42 N | 087 44 47 W |
| Congregational Bible Church | Church | 198 | Bureau | 41 21 44 N | 089 35 00 W |
| Congregational Christian Church | Church | 143 | Richland | 38 43 51 N | 088 05 14 W |
| Congregational Church | Church | 187 | Rock Island | 41 36 19 N | 090 20 04 W |
| Congregational Church | Church | 174 | Tazewell | 40 34 28 N | 089 36 59 W |
| Congregational Church of Algonquin | Church | 225 | McHenry | 42 09 54 N | 088 17 36 W |
| Congregational Church of Batavia | Church | 217 | Kane | 41 50 56 N | 088 18 44 W |
| Congregational Church of Deerfield | Church | 206 | Lake | 42 09 26 N | 087 52 01 W |
| Congregational Church of Jefferson Park | Church | 188 | Cook | 41 57 59 N | 087 45 39 W |
| Congregational Church of Lily Lake | Church | 293 | Kane | 41 56 57 N | 088 28 34 W |
| Congregational United Church | Church | 215 | Cook | 42 04 15 N | 087 59 44 W |
| Congregational Universalist Church of Woodstock | Church | 285 | McHenry | 42 18 47 N | 088 26 50 W |
| Congress Park Elementary School | School | 190 | Cook | 41 48 44 N | 087 51 16 W |
| Congress Plaza | Locale | 184 | Cook | 41 52 32 N | 087 37 16 W |
| Congress School | School | 268 | Ogle | 41 59 17 N | 089 34 48 W |
| Conkey Branch | Stream | | Champaign | 40 03 34 N | 087 58 56 W |
| Conkey Cemetery | Cemetery | 198 | Edgar | 39 40 46 N | 087 39 01 W |
| Conklin Elementary School | School | 235 | Winnebago | 42 18 38 N | 089 06 13 W |
| Conklin Park | Park | 235 | Winnebago | 42 18 40 N | 089 06 17 W |
| Conklin School (historical) | School | 178 | Grundy | 41 26 43 N | 088 25 23 W |
| Conlee Cemetery | Cemetery | 212 | Morgan | 39 32 03 N | 089 57 31 W |
| Conley Chapel (historical) | Church | 143 | Clay | 38 47 32 N | 088 24 36 W |
| Conley Ditch | Canal | 187 | Bureau | 41 27 36 N | 089 47 47 W |
| Conley School (historical) | School | 205 | Bureau | 41 27 36 N | 089 45 09 W |
| Conleys Patch (subdivision) | Populated Place | 179 | Cook | 41 51 51 N | 087 38 10 W |
| Conlogue | Populated Place | 219 | Edgar | 39 35 24 N | 087 47 35 W |
| Conlogue School (historical) | School | 219 | Edgar | 39 34 35 N | 087 47 25 W |
| Conly Cemetery | Cemetery | 154 | Clay | 38 52 21 N | 088 29 24 W |
| Connelly Cemetery | Cemetery | 176 | Clark | 39 19 18 N | 087 55 22 W |
| Connelly Ford | Crossing | 161 | Clark | 39 15 09 N | 087 55 30 W |
| Connelly Park | Park | 207 | DuPage | 41 48 10 N | 088 04 17 W |
| Connelly School (historical) | School | 235 | Coles | 39 27 39 N | 088 01 34 W |
| Conner College (historical) | School | 132 | Franklin | 38 04 42 N | 088 55 48 W |
| Conners Branch | Stream | | Marion | 38 37 53 N | 088 43 57 W |
| Conners Chapel | Church | 159 | Clay | 38 41 40 N | 088 40 37 W |
| Conners Gymnasium | Building | 180 | Cook | 41 47 31 N | 087 35 55 W |
| Conness School (historical) | School | 200 | La Salle | 41 08 55 N | 088 56 08 W |
| Connolly Park | Park | 237 | Ogle | 41 54 39 N | 089 04 00 W |
| Connor Cemetery | Cemetery | 188 | Fulton | 40 27 31 N | 090 09 28 W |
| Conover | Populated Place | 149 | Mason | 40 10 38 N | 090 01 26 W |
| Conover Branch | Stream | | Morgan | 39 50 15 N | 090 08 45 W |
| Conover Cemetery | Cemetery | 147 | Lawrence | 38 50 50 N | 087 41 45 W |
| Conover School (historical) | School | 160 | Lawrence | 38 50 12 N | 087 42 10 W |
| Conover School (historical) | School | 227 | Marshall | 41 08 30 N | 089 34 58 W |
| Conrad | Populated Place | 190 | Calhoun | 38 55 31 N | 090 37 01 W |
| Conrad Baptist Cemetery | Cemetery | 212 | Clark | 39 27 56 N | 087 56 30 W |
| Conrad Fischer Elementary School | School | 207 | DuPage | 41 55 35 N | 087 56 05 W |
| Conrad Fisher Park | Park | 207 | DuPage | 41 55 38 N | 087 56 08 W |
| Conrad Park | Park | 176 | Greene | 39 26 38 N | 090 24 15 W |
| Conroy Island | Island | 160 | Will | 41 24 00 N | 088 13 35 W |
| Conservation Lake | Reservoir | 149 | Wabash | 38 26 47 N | 087 48 56 W |
| Constance Hall | Building | 183 | Peoria | 40 41 47 N | 089 36 51 W |
| Constant Cemetery | Cemetery | 205 | Sangamon | 39 54 25 N | 089 25 34 W |
| Constitution Park | Park | 189 | Cook | 41 54 16 N | 087 49 04 W |
| Constitution Park | Park | 199 | Lake | 42 18 56 N | 087 50 11 W |
| Contemporary Art Workshop | School | 183 | Cook | 41 55 22 N | 087 38 35 W |