| Watford to Mancha Real | 970.90 mi (1,562.52 km) |
| Watford to Manilva | 1,081.77 mi (1,740.94 km) |
| Watford to Manises | 840.99 mi (1,353.44 km) |
| Watford to Manlleu | 678.89 mi (1,092.57 km) |
| Watford to Manresa | 693.97 mi (1,116.83 km) |
| Watford to Manzanares | 886.31 mi (1,426.37 km) |
| Watford to Manzanares el Real | 772.78 mi (1,243.68 km) |
| Watford to Maracena | 1,011.18 mi (1,627.33 km) |
| Watford to Marbella | 1,068.88 mi (1,720.20 km) |
| Watford to Marchena | 1,019.39 mi (1,640.54 km) |
| Watford to Marin | 748.90 mi (1,205.24 km) |
| Watford to Marratxi | 843.62 mi (1,357.67 km) |
| Watford to Martorell | 711.94 mi (1,145.76 km) |
| Watford to Martos | 978.58 mi (1,574.87 km) |
| Watford to Masamagrell | 834.98 mi (1,343.77 km) |
