| Ontario to Castle Pines (Colorado) | 797.36 mi (1,283.23 km) |
| Ontario to Castle Rock (Colorado) | 795.79 mi (1,280.70 km) |
| Ontario to Castro Valley (California) | 355.61 mi (572.30 km) |
| Ontario to Catalina Foothills (Arizona) | 406.75 mi (654.60 km) |
| Ontario to Cataño (Puerto Rico) | 3,328.83 mi (5,357.23 km) |
| Ontario to Cathedral City (California) | 66.96 mi (107.76 km) |
| Ontario to Catonsville (Maryland) | 2,274.25 mi (3,660.06 km) |
| Ontario to Cave Spring (Virginia) | 2,109.08 mi (3,394.23 km) |
| Ontario to Cayce (South Carolina) | 2,083.17 mi (3,352.55 km) |
| Ontario to Cayey (Puerto Rico) | 3,338.78 mi (5,373.25 km) |
| Ontario to Cedar City (Utah) | 356.55 mi (573.81 km) |
| Ontario to Cedar Falls (Iowa) | 1,477.54 mi (2,377.87 km) |
| Ontario to Cedar Hill (Texas) | 1,194.44 mi (1,922.26 km) |
| Ontario to Cedar Lake (Indiana) | 1,715.18 mi (2,760.32 km) |
| Ontario to Cedar Mill (Oregon) | 840.34 mi (1,352.40 km) |
