| Rhondda to McKeesport (Pennsylvania) | 3,578.54 mi (5,759.11 km) |
| Rhondda to McKinleyville (California) | 5,117.51 mi (8,235.83 km) |
| Rhondda to McKinney (Texas) | 4,590.24 mi (7,387.27 km) |
| Rhondda to McLean (Virginia) | 3,532.38 mi (5,684.82 km) |
| Rhondda to McMinnville (Oregon) | 4,848.88 mi (7,803.53 km) |
| Rhondda to McMinnville (Tennessee) | 4,033.66 mi (6,491.55 km) |
| Rhondda to McNair (Virginia) | 3,540.98 mi (5,698.65 km) |
| Rhondda to McPherson (Kansas) | 4,368.05 mi (7,029.70 km) |
| Rhondda to Mead Valley (California) | 5,308.85 mi (8,543.76 km) |
| Rhondda to Meadow Woods (Florida) | 4,206.06 mi (6,768.99 km) |
| Rhondda to Meadowbrook (Virginia) | 3,611.86 mi (5,812.72 km) |
| Rhondda to Meadville (Pennsylvania) | 3,533.40 mi (5,686.46 km) |
| Rhondda to Mebane (North Carolina) | 3,748.04 mi (6,031.88 km) |
| Rhondda to Mechanicsville (Virginia) | 3,598.10 mi (5,790.58 km) |
| Rhondda to Medford (Massachusetts) | 3,133.29 mi (5,042.54 km) |
