| Merthyr Tudful to Decatur (Georgia) | 4,064.01 mi (6,540.40 km) |
| Merthyr Tudful to Decatur (Illinois) | 3,959.91 mi (6,372.87 km) |
| Merthyr Tudful to Deer Park (New York) | 3,292.94 mi (5,299.47 km) |
| Merthyr Tudful to Deer Park (Texas) | 4,706.79 mi (7,574.85 km) |
| Merthyr Tudful to Deerfield (Illinois) | 3,811.07 mi (6,133.33 km) |
| Merthyr Tudful to Deerfield Beach (Florida) | 4,258.04 mi (6,852.65 km) |
| Merthyr Tudful to Defiance (Ohio) | 3,715.50 mi (5,979.51 km) |
| Merthyr Tudful to DeForest (Wisconsin) | 3,819.41 mi (6,146.75 km) |
| Merthyr Tudful to DeKalb (Illinois) | 3,856.22 mi (6,205.99 km) |
| Merthyr Tudful to Del Aire (California) | 5,335.95 mi (8,587.38 km) |
| Merthyr Tudful to Del City (Oklahoma) | 4,503.90 mi (7,248.33 km) |
| Merthyr Tudful to Del Rio (Texas) | 4,951.13 mi (7,968.08 km) |
| Merthyr Tudful to DeLand (Florida) | 4,171.29 mi (6,713.04 km) |
| Merthyr Tudful to Delano (California) | 5,260.50 mi (8,465.96 km) |
| Merthyr Tudful to Delaware (Ohio) | 3,709.31 mi (5,969.55 km) |
