| Merthyr Tudful to Dumas (Texas) | 4,653.46 mi (7,489.02 km) |
| Merthyr Tudful to Dumont (New Jersey) | 3,312.71 mi (5,331.29 km) |
| Merthyr Tudful to Duncan (Oklahoma) | 4,568.45 mi (7,352.21 km) |
| Merthyr Tudful to Duncanville (Texas) | 4,626.15 mi (7,445.07 km) |
| Merthyr Tudful to Dundalk (Maryland) | 3,488.26 mi (5,613.82 km) |
| Merthyr Tudful to Dunedin (Florida) | 4,283.62 mi (6,893.83 km) |
| Merthyr Tudful to Dunkirk (New York) | 3,463.23 mi (5,573.53 km) |
| Merthyr Tudful to Dunmore (Pennsylvania) | 3,358.68 mi (5,405.27 km) |
| Merthyr Tudful to Dunwoody (Georgia) | 4,056.42 mi (6,528.18 km) |
| Merthyr Tudful to Durango (Colorado) | 4,794.01 mi (7,715.21 km) |
| Merthyr Tudful to Durant (Oklahoma) | 4,537.11 mi (7,301.77 km) |
| Merthyr Tudful to Durham (North Carolina) | 3,736.96 mi (6,014.05 km) |
| Merthyr Tudful to Dyer (Indiana) | 3,828.39 mi (6,161.20 km) |
| Merthyr Tudful to Dyersburg (Tennessee) | 4,159.32 mi (6,693.79 km) |
| Merthyr Tudful to Eagan (Minnesota) | 3,888.66 mi (6,258.20 km) |
