| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Cabery | city | Illinois | United States | 41.00 | -88.21 | 830 | |
| Cable | city | Illinois | United States | 41.28 | -90.51 | 830 | |
| Cabrini Addition | city | Illinois | United States | 41.90 | -87.64 | 830 | |
| Cache | city | Illinois | United States | 37.10 | -89.26 | 321 | |
| Cache Lake | city | Illinois | United States | 41.64 | -88.01 | 830 | |
| Cadiz | city | Illinois | United States | 37.58 | -88.23 | 830 | |
| Cadwell | city | Illinois | United States | 39.68 | -88.52 | 830 | |
| Cahokia | city | Illinois | United States | 38.57 | -90.19 | 406 | |
| Cairo | city | Illinois | United States | 37.01 | -89.18 | 305 | |
| Cairo Junction | city | Illinois | United States | 37.04 | -89.19 | 308 | |
| Caldwell | city | Illinois | United States | 40.64 | -89.52 | 830 | |
| Caledonia | city | Illinois | United States | 42.37 | -88.89 | 948 | |
| Caledonia (historical) | city | Illinois | United States | 41.12 | -89.25 | 830 | |
| Calftown (historical) | city | Illinois | United States | 39.93 | -91.40 | 830 | |
| Calhoun | city | Illinois | United States | 38.65 | -88.04 | 830 | |
| California Park | city | Illinois | United States | 41.96 | -87.70 | 830 | |
| Calumet | city | Illinois | United States | 41.73 | -87.55 | 830 | |
| Calumet City | city | Illinois | United States | 41.62 | -87.53 | 830 | |
| Calumet Heights | city | Illinois | United States | 41.73 | -87.58 | 830 | |
| Calumet Park | city | Illinois | United States | 41.66 | -87.66 | 830 | |
| Calvin | city | Illinois | United States | 38.21 | -88.02 | 830 | |
| Camargo | city | Illinois | United States | 39.80 | -88.16 | 830 | |
| Cambon | city | Illinois | United States | 37.90 | -89.00 | 396 | |
| Cambria | city | Illinois | United States | 37.78 | -89.12 | 830 | |
| Cambridge | city | Illinois | United States | 41.30 | -90.19 | 830 | |
| Cambridge Place | city | Illinois | United States | 41.63 | -88.17 | 830 | |
| Camden | city | Illinois | United States | 40.15 | -90.77 | 830 | |
| Camden | city | Illinois | United States | 38.97 | -90.46 | 830 | |
| Cameron | city | Illinois | United States | 40.89 | -90.52 | 830 | |
| Camp Algonquin | city | Illinois | United States | 42.18 | -88.27 | 830 | |
| Camp Ground | city | Illinois | United States | 38.34 | -88.84 | 830 | |
| Camp Grove | city | Illinois | United States | 41.08 | -89.63 | 846 | |
| Camp Logan | city | Illinois | United States | 42.46 | -87.82 | 830 | |
| Camp Point | city | Illinois | United States | 40.04 | -91.07 | 830 | |
| Camp Travis | city | Illinois | United States | 38.66 | -88.33 | 830 | |
| Campbell | city | Illinois | United States | 39.40 | -88.21 | 830 | |
| Campbell | city | Illinois | United States | 40.19 | -87.58 | 830 | |
| Campbell | city | Illinois | United States | 38.36 | -88.46 | 403 | |
| Campbell Hill | city | Illinois | United States | 37.93 | -89.55 | 830 | |
| Campbellsburg (historical) | city | Illinois | United States | 39.68 | -89.42 | 830 | |
| Campifons | city | Illinois | United States | 39.80 | -89.64 | 830 | |
| Campton | city | Illinois | United States | 37.93 | -89.80 | 830 | |
| Campton Hills | city | Illinois | United States | 41.94 | -88.40 | 830 | |
| Campton Pines | city | Illinois | United States | 41.92 | -88.39 | 849 | |
| Campus | city | Illinois | United States | 41.02 | -88.31 | 830 | |
| Canal Trustees | city | Illinois | United States | 41.90 | -87.63 | 830 | |
| Canalport | city | Illinois | United States | 41.84 | -87.67 | 830 | |
| Canaryville | city | Illinois | United States | 41.81 | -87.64 | 830 | |
| Candlewick Lake | city | Illinois | United States | 42.35 | -88.86 | 898 | |
| Canton | city | Illinois | United States | 40.56 | -90.04 | 830 | |
| Canton Crossing | city | Illinois | United States | 41.56 | -88.19 | 830 | |
| Cantrall | city | Illinois | United States | 39.94 | -89.68 | 830 | |
| Canyon Ridge | city | Illinois | United States | 42.20 | -89.05 | 830 | |
| Capitol Oaks | city | Illinois | United States | 38.59 | -89.97 | 830 | |
| Capri Village | city | Illinois | United States | 42.14 | -88.03 | 830 | |
| Capron | city | Illinois | United States | 42.40 | -88.74 | 915 | |
| Carbon | city | Illinois | United States | 38.59 | -89.94 | 830 | |
| Carbon Cliff | city | Illinois | United States | 41.49 | -90.39 | 830 | |
| Carbon Hill | city | Illinois | United States | 41.30 | -88.30 | 830 | |
| Carbondale | city | Illinois | United States | 37.73 | -89.22 | 403 | |
| Cardiff | city | Illinois | United States | 41.05 | -88.29 | 830 | |
| Cardinal Court | city | Illinois | United States | 40.52 | -89.00 | 830 | |
| Carillon | city | Illinois | United States | 41.63 | -88.13 | 830 | |
| Carl Sandburg Village | city | Illinois | United States | 41.91 | -87.63 | 830 | |
| Carle Springs | city | Illinois | United States | 40.25 | -88.97 | 830 | |
| Carlinville | city | Illinois | United States | 39.28 | -89.88 | 830 | |
| Carlock | city | Illinois | United States | 40.58 | -89.13 | 830 | |
| Carlsburg | city | Illinois | United States | 39.08 | -89.72 | 830 | |
| Carlye Subdivision | city | Illinois | United States | 42.14 | -87.87 | 830 | |
| Carlyle | city | Illinois | United States | 38.61 | -89.37 | 830 | |
| Carman | city | Illinois | United States | 40.74 | -91.06 | 830 | |
| Carmi | city | Illinois | United States | 38.09 | -88.16 | 354 | |
| Carol Stream | city | Illinois | United States | 41.91 | -88.13 | 830 | |
| Carpenter | city | Illinois | United States | 38.89 | -89.89 | 830 | |
| Carpenters Addition | city | Illinois | United States | 41.89 | -87.65 | 830 | |
| Carpentersville | city | Illinois | United States | 42.12 | -88.26 | 902 | |
| Carriage Lane Estates | city | Illinois | United States | 41.10 | -88.82 | 830 | |
| Carrier Mills | city | Illinois | United States | 37.68 | -88.63 | 393 | |
| Carrollton | city | Illinois | United States | 39.30 | -90.41 | 830 | |
| Carterville | city | Illinois | United States | 37.76 | -89.08 | 830 | |
| Carthage | city | Illinois | United States | 41.92 | -89.31 | 830 | |
| Carthage | city | Illinois | United States | 40.42 | -91.14 | 830 | |
| Carthage Lake | city | Illinois | United States | 40.79 | -91.08 | 830 | |
| Cartter | city | Illinois | United States | 38.54 | -88.91 | 830 | |
| Carville | city | Illinois | United States | 41.85 | -87.62 | 830 | |
| Cary | city | Illinois | United States | 42.21 | -88.24 | 830 | |
| Cascade | city | Illinois | United States | 39.67 | -89.49 | 830 | |
| Casey | city | Illinois | United States | 39.30 | -87.99 | 830 | |
| Caseyville | city | Illinois | United States | 38.64 | -90.03 | 830 | |
| Casner | city | Illinois | United States | 39.80 | -88.79 | 830 | |
| Caspars | city | Illinois | United States | 38.30 | -89.66 | 830 | |
| Cass (historical) | city | Illinois | United States | 39.97 | -90.27 | 830 | |
| Castle Fin | city | Illinois | United States | 39.47 | -87.73 | 830 | |
| Castle Junction | city | Illinois | United States | 41.39 | -90.58 | 830 | |
| Castleton | city | Illinois | United States | 41.12 | -89.71 | 830 | |
| Catfish (historical) | city | Illinois | United States | 39.67 | -87.93 | 830 | |
| Catharine | city | Illinois | United States | 41.52 | -88.72 | 830 | |
| Catlin | city | Illinois | United States | 40.07 | -87.70 | 830 | |
| Caton Farm | city | Illinois | United States | 41.57 | -88.24 | 830 | |
| Cave-in-Rock | city | Illinois | United States | 37.47 | -88.17 | 331 | |
| Cayuga | city | Illinois | United States | 40.94 | -88.58 | 830 | |
| Cazenovia | city | Illinois | United States | 40.85 | -89.33 | 830 |