| Rhondda to Mauldin (South Carolina) | 3,934.39 mi (6,331.79 km) |
| Rhondda to Maumee (Ohio) | 3,676.77 mi (5,917.19 km) |
| Rhondda to Maumelle (Arkansas) | 4,339.51 mi (6,983.76 km) |
| Rhondda to Mayagüez (Puerto Rico) | 4,118.21 mi (6,627.61 km) |
| Rhondda to Mayfield Heights (Ohio) | 3,591.34 mi (5,779.71 km) |
| Rhondda to Mays Chapel (Maryland) | 3,488.35 mi (5,613.96 km) |
| Rhondda to Maywood (California) | 5,330.17 mi (8,578.07 km) |
| Rhondda to Maywood (Illinois) | 3,826.13 mi (6,157.56 km) |
| Rhondda to McAlester (Oklahoma) | 4,468.20 mi (7,190.87 km) |
| Rhondda to McAllen (Texas) | 5,014.28 mi (8,069.70 km) |
| Rhondda to McCalla (Alabama) | 4,199.69 mi (6,758.75 km) |
| Rhondda to McComb (Mississippi) | 4,441.80 mi (7,148.39 km) |
| Rhondda to McDonough (Georgia) | 4,074.85 mi (6,557.84 km) |
| Rhondda to McFarland (California) | 5,269.28 mi (8,480.08 km) |
| Rhondda to McHenry (Illinois) | 3,822.51 mi (6,151.73 km) |
