| Merthyr Tudful to Kinston (North Carolina) | 3,715.39 mi (5,979.35 km) |
| Merthyr Tudful to Kirkland (Washington) | 4,676.08 mi (7,525.42 km) |
| Merthyr Tudful to Kirksville (Missouri) | 4,083.83 mi (6,572.28 km) |
| Merthyr Tudful to Kirkwood (Missouri) | 4,078.32 mi (6,563.42 km) |
| Merthyr Tudful to Kiryas Joel (New York) | 3,303.01 mi (5,315.69 km) |
| Merthyr Tudful to Kissimmee (Florida) | 4,212.44 mi (6,779.27 km) |
| Merthyr Tudful to Klamath Falls (Oregon) | 4,972.38 mi (8,002.28 km) |
| Merthyr Tudful to Knightdale (North Carolina) | 3,728.89 mi (6,001.07 km) |
| Merthyr Tudful to Knik-Fairview (Alaska) | 4,394.71 mi (7,072.60 km) |
| Merthyr Tudful to Knoxville (Tennessee) | 3,944.61 mi (6,348.24 km) |
| Merthyr Tudful to Kokomo (Indiana) | 3,821.96 mi (6,150.85 km) |
| Merthyr Tudful to Kuna (Idaho) | 4,740.28 mi (7,628.74 km) |
| Merthyr Tudful to Kyle (Texas) | 4,801.18 mi (7,726.75 km) |
| Merthyr Tudful to La Cañada Flintridge (California) | 5,313.83 mi (8,551.78 km) |
| Merthyr Tudful to La Crescenta-Montrose (California) | 5,313.71 mi (8,551.59 km) |
