| Harpenden to Nasaud | 1,146.95 mi (1,845.84 km) |
| Harpenden to Navodari | 1,422.52 mi (2,289.33 km) |
| Harpenden to Negresti-Oas | 1,088.58 mi (1,751.90 km) |
| Harpenden to Nehoiu | 1,288.88 mi (2,074.25 km) |
| Harpenden to Ocna Mures | 1,151.29 mi (1,852.82 km) |
| Harpenden to Odobesti | 1,307.08 mi (2,103.54 km) |
| Harpenden to Odorheiu Secuiesc | 1,214.60 mi (1,954.71 km) |
| Harpenden to Oltenita | 1,348.36 mi (2,169.97 km) |
| Harpenden to Onesti | 1,278.52 mi (2,057.58 km) |
| Harpenden to Oradea | 1,048.08 mi (1,686.72 km) |
| Harpenden to Orastie | 1,141.54 mi (1,837.14 km) |
| Harpenden to Oravita | 1,107.84 mi (1,782.89 km) |
| Harpenden to Orsova | 1,148.87 mi (1,848.93 km) |
| Harpenden to Otelu Rosu | 1,117.85 mi (1,799.01 km) |
| Harpenden to Otopeni | 1,307.55 mi (2,104.29 km) |
