| Riviera Beach to Mangualde | 4,149.36 mi (6,677.75 km) |
| Riviera Beach to Marco de Canavezes | 4,121.95 mi (6,633.63 km) |
| Riviera Beach to Marinha Grande | 4,099.79 mi (6,597.98 km) |
| Riviera Beach to Massama | 4,095.00 mi (6,590.27 km) |
| Riviera Beach to Matosinhos | 4,093.81 mi (6,588.35 km) |
| Riviera Beach to Mealhada | 4,116.69 mi (6,625.18 km) |
| Riviera Beach to Melgaco | 4,104.64 mi (6,605.78 km) |
| Riviera Beach to Melres | 4,110.61 mi (6,615.38 km) |
| Riviera Beach to Mira | 4,101.41 mi (6,600.58 km) |
| Riviera Beach to Miranda do Corvo | 4,126.43 mi (6,640.85 km) |
| Riviera Beach to Mirandela | 4,167.46 mi (6,706.87 km) |
| Riviera Beach to Mogadouro | 4,193.12 mi (6,748.17 km) |
| Riviera Beach to Moimenta da Beira | 4,152.00 mi (6,682.01 km) |
| Riviera Beach to Moita | 4,111.87 mi (6,617.41 km) |
| Riviera Beach to Moncao | 4,094.38 mi (6,589.26 km) |
