| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Coal City | city | Illinois | United States | 41.29 | -88.29 | 830 | |
| Coal Hollow | city | Illinois | United States | 41.37 | -89.36 | 830 | |
| Coal Valley | city | Illinois | United States | 41.43 | -90.46 | 830 | |
| Coaler | city | Illinois | United States | 40.75 | -87.73 | 830 | |
| Coalton | city | Illinois | United States | 40.43 | -87.59 | 830 | |
| Coalton | city | Illinois | United States | 39.28 | -89.30 | 830 | |
| Coalville | city | Illinois | United States | 41.09 | -88.85 | 830 | |
| Coatsburg | city | Illinois | United States | 40.03 | -91.16 | 830 | |
| Cobblewood | city | Illinois | United States | 42.10 | -87.84 | 830 | |
| Cobden | city | Illinois | United States | 37.53 | -89.25 | 830 | |
| Cody | city | Illinois | United States | 39.77 | -89.72 | 830 | |
| Coello | city | Illinois | United States | 37.99 | -89.07 | 830 | |
| Coffeen | city | Illinois | United States | 39.09 | -89.39 | 830 | |
| Colby Point | city | Illinois | United States | 42.30 | -88.24 | 830 | |
| Colchester | city | Illinois | United States | 40.43 | -90.79 | 830 | |
| Coldbrook | city | Illinois | United States | 40.95 | -90.52 | 830 | |
| Coleman | city | Illinois | United States | 41.98 | -88.30 | 830 | |
| Coleman | city | Illinois | United States | 39.76 | -89.69 | 830 | |
| Coles | city | Illinois | United States | 39.52 | -88.47 | 830 | |
| Coleta | city | Illinois | United States | 41.90 | -89.80 | 830 | |
| Colfax | city | Illinois | United States | 40.57 | -88.62 | 830 | |
| Collins | city | Illinois | United States | 38.02 | -89.95 | 413 | |
| Collins (historical) | city | Illinois | United States | 41.07 | -87.70 | 830 | |
| Collinsville | city | Illinois | United States | 38.67 | -89.98 | 830 | |
| Collison | city | Illinois | United States | 40.23 | -87.80 | 830 | |
| Colmar | city | Illinois | United States | 40.35 | -90.89 | 830 | |
| Colona | city | Illinois | United States | 41.48 | -90.35 | 830 | |
| Colonial Acres | city | Illinois | United States | 41.57 | -87.99 | 830 | |
| Colonial Gardens | city | Illinois | United States | 42.33 | -89.09 | 830 | |
| Colonial Gardens | city | Illinois | United States | 41.97 | -87.78 | 830 | |
| Colonial Meadows | city | Illinois | United States | 40.48 | -88.93 | 846 | |
| Colonial Village | city | Illinois | United States | 42.13 | -87.81 | 830 | |
| Colonial Village | city | Illinois | United States | 41.70 | -88.05 | 830 | |
| Colp | city | Illinois | United States | 37.81 | -89.08 | 400 | |
| Columbia | city | Illinois | United States | 38.44 | -90.20 | 830 | |
| Columbiana (historical) | city | Illinois | United States | 39.30 | -90.60 | 830 | |
| Columbus | city | Illinois | United States | 39.99 | -91.15 | 830 | |
| Columbus (historical) | city | Illinois | United States | 39.76 | -90.60 | 830 | |
| Colusa | city | Illinois | United States | 40.57 | -91.17 | 830 | |
| Colvin Park | city | Illinois | United States | 42.14 | -88.78 | 849 | |
| Combs | city | Illinois | United States | 40.12 | -88.61 | 830 | |
| Comer | city | Illinois | United States | 39.29 | -89.97 | 830 | |
| Commanche Village | city | Illinois | United States | 39.59 | -89.62 | 830 | |
| Como | city | Illinois | United States | 41.77 | -89.77 | 830 | |
| Compro | city | Illinois | United States | 39.59 | -89.78 | 830 | |
| Compton | city | Illinois | United States | 41.69 | -89.08 | 944 | |
| Conant | city | Illinois | United States | 38.06 | -89.48 | 830 | |
| Concord | city | Illinois | United States | 39.82 | -90.37 | 830 | |
| Confidence | city | Illinois | United States | 38.92 | -88.93 | 830 | |
| Congerville | city | Illinois | United States | 40.62 | -89.20 | 830 | |
| Conleys Patch | city | Illinois | United States | 41.86 | -87.64 | 830 | |
| Conlogue | city | Illinois | United States | 39.59 | -87.79 | 830 | |
| Conover | city | Illinois | United States | 40.18 | -90.02 | 830 | |
| Conrad | city | Illinois | United States | 38.93 | -90.62 | 830 | |
| Conwayville (historical) | city | Illinois | United States | 39.24 | -90.40 | 830 | |
| Cookes Subdivision | city | Illinois | United States | 41.67 | -87.63 | 830 | |
| Cooks Mills | city | Illinois | United States | 39.58 | -88.41 | 830 | |
| Cooksville | city | Illinois | United States | 40.54 | -88.72 | 830 | |
| Cooper | city | Illinois | United States | 40.66 | -89.40 | 830 | |
| Cooperstown | city | Illinois | United States | 39.96 | -90.61 | 830 | |
| Copperfield | city | Illinois | United States | 42.22 | -88.08 | 866 | |
| Cora | city | Illinois | United States | 37.82 | -89.67 | 370 | |
| Coral | city | Illinois | United States | 42.22 | -88.56 | 895 | |
| Coral Manor | city | Illinois | United States | 42.13 | -87.86 | 830 | |
| Cordes | city | Illinois | United States | 38.30 | -89.46 | 830 | |
| Cordova | city | Illinois | United States | 41.68 | -90.32 | 830 | |
| Coreys Bluff | city | Illinois | United States | 42.24 | -89.12 | 830 | |
| Corinth | city | Illinois | United States | 37.82 | -88.78 | 830 | |
| Cornell | city | Illinois | United States | 40.99 | -88.73 | 830 | |
| Cornell | city | Illinois | United States | 41.75 | -87.60 | 830 | |
| Cornerville | city | Illinois | United States | 37.91 | -88.62 | 830 | |
| Cornland | city | Illinois | United States | 39.94 | -89.40 | 830 | |
| Cortland | city | Illinois | United States | 41.92 | -88.69 | 898 | |
| Corwith | city | Illinois | United States | 41.82 | -87.71 | 830 | |
| Cotswald Subdivision | city | Illinois | United States | 42.14 | -87.84 | 830 | |
| Cottage Grove | city | Illinois | United States | 37.75 | -88.41 | 400 | |
| Cottage Hills | city | Illinois | United States | 38.90 | -90.07 | 830 | |
| Cotton Hill | city | Illinois | United States | 39.70 | -89.63 | 830 | |
| Cottonwood | city | Illinois | United States | 37.89 | -88.21 | 400 | |
| Coughlin | city | Illinois | United States | 40.90 | -89.50 | 830 | |
| Coulterville | city | Illinois | United States | 38.19 | -89.61 | 830 | |
| Council Hill | city | Illinois | United States | 42.49 | -90.35 | 898 | |
| Country Acres Mobile Manor | city | Illinois | United States | 41.76 | -89.73 | 830 | |
| Country Air Mobile Home Estates | city | Illinois | United States | 42.34 | -90.00 | 1053 | |
| Country Club Estates | city | Illinois | United States | 39.47 | -88.33 | 830 | |
| Country Club Estates | city | Illinois | United States | 42.16 | -88.01 | 830 | |
| Country Club Hills | city | Illinois | United States | 41.57 | -87.72 | 830 | |
| Country Hills | city | Illinois | United States | 41.40 | -87.79 | 830 | |
| Country Meadows | city | Illinois | United States | 39.98 | -91.36 | 830 | |
| Country Meadows | city | Illinois | United States | 41.42 | -87.72 | 830 | |
| Country Oaks | city | Illinois | United States | 41.42 | -87.75 | 830 | |
| Country Squire | city | Illinois | United States | 41.63 | -87.98 | 830 | |
| Country View Estates | city | Illinois | United States | 41.72 | -88.17 | 830 | |
| Countryside | city | Illinois | United States | 41.66 | -88.45 | 830 | |
| Countryside | city | Illinois | United States | 41.78 | -87.88 | 830 | |
| Countryside East | city | Illinois | United States | 42.19 | -88.08 | 849 | |
| Countryside West | city | Illinois | United States | 42.17 | -88.08 | 846 | |
| County Glen | city | Illinois | United States | 41.54 | -88.19 | 830 | |
| Covell | city | Illinois | United States | 40.44 | -89.11 | 830 | |
| Covenant Village | city | Illinois | United States | 42.11 | -87.84 | 830 | |
| Coventry Creek | city | Illinois | United States | 42.21 | -89.00 | 830 | |
| Coventry Heights | city | Illinois | United States | 41.54 | -88.00 | 830 | |
| Coventry Hills | city | Illinois | United States | 42.23 | -89.00 | 830 | |
| Coventry Hills East | city | Illinois | United States | 42.23 | -88.99 | 830 | |
| Covington | city | Illinois | United States | 38.45 | -89.44 | 830 | |
| Covington | city | Illinois | United States | 38.40 | -88.49 | 830 | |
| Cowden | city | Illinois | United States | 39.25 | -88.86 | 830 | |
| Cowling | city | Illinois | United States | 38.31 | -87.94 | 383 | |
| Coyne | city | Illinois | United States | 42.18 | -88.45 | 872 | |
| Coyne Center | city | Illinois | United States | 41.40 | -90.56 | 830 | |
| Coynes | city | Illinois | United States | 41.58 | -88.14 | 830 | |
| Cozy Corner | city | Illinois | United States | 42.12 | -87.86 | 830 |