| Merthyr Tudful to Cookeville (Tennessee) | 3,999.41 mi (6,436.43 km) |
| Merthyr Tudful to Coolidge (Arizona) | 5,156.30 mi (8,298.27 km) |
| Merthyr Tudful to Coon Rapids (Minnesota) | 3,877.45 mi (6,240.15 km) |
| Merthyr Tudful to Cooper City (Florida) | 4,277.79 mi (6,884.45 km) |
| Merthyr Tudful to Coos Bay (Oregon) | 4,976.84 mi (8,009.46 km) |
| Merthyr Tudful to Copiague (New York) | 3,299.75 mi (5,310.43 km) |
| Merthyr Tudful to Coppell (Texas) | 4,612.91 mi (7,423.77 km) |
| Merthyr Tudful to Copperas Cove (Texas) | 4,743.92 mi (7,634.61 km) |
| Merthyr Tudful to Coral Gables (Florida) | 4,294.47 mi (6,911.27 km) |
| Merthyr Tudful to Coral Springs (Florida) | 4,265.36 mi (6,864.44 km) |
| Merthyr Tudful to Coral Terrace (Florida) | 4,293.73 mi (6,910.08 km) |
| Merthyr Tudful to Coralville (Iowa) | 3,975.55 mi (6,398.03 km) |
| Merthyr Tudful to Coram (New York) | 3,274.87 mi (5,270.39 km) |
| Merthyr Tudful to Corcoran (California) | 5,252.05 mi (8,452.36 km) |
| Merthyr Tudful to Cordele (Georgia) | 4,130.51 mi (6,647.42 km) |
