| Harpenden to Peterborough | 51.96 mi (83.62 km) |
| Harpenden to Peterhead | 397.36 mi (639.49 km) |
| Harpenden to Peterlee | 207.27 mi (333.57 km) |
| Harpenden to Petersfield | 61.61 mi (99.16 km) |
| Harpenden to Pinner | 15.58 mi (25.07 km) |
| Harpenden to Pitsea | 40.50 mi (65.18 km) |
| Harpenden to Plumstead | 29.52 mi (47.51 km) |
| Harpenden to Plymouth | 192.39 mi (309.62 km) |
| Harpenden to Plympton | 188.47 mi (303.31 km) |
| Harpenden to Plymstock | 191.01 mi (307.40 km) |
| Harpenden to Polegate | 73.47 mi (118.24 km) |
| Harpenden to Ponders End | 17.67 mi (28.44 km) |
| Harpenden to Pont-y-pwl | 115.24 mi (185.47 km) |
| Harpenden to Pontardulais | 157.85 mi (254.03 km) |
| Harpenden to Pontefract | 135.52 mi (218.10 km) |
