| Harrow Weald to Opole | 792.75 mi (1,275.81 km) |
| Harrow Weald to Orzesze | 835.83 mi (1,345.14 km) |
| Harrow Weald to Osowa | 803.16 mi (1,292.56 km) |
| Harrow Weald to Ostroda | 860.29 mi (1,384.50 km) |
| Harrow Weald to Ostroleka | 926.66 mi (1,491.32 km) |
| Harrow Weald to Ostrow Mazowiecka | 941.55 mi (1,515.28 km) |
| Harrow Weald to Ostrow Wielkopolski | 776.72 mi (1,250.01 km) |
| Harrow Weald to Ostrowiec Swietokrzyski | 937.44 mi (1,508.66 km) |
| Harrow Weald to Ostrzeszow | 783.80 mi (1,261.41 km) |
| Harrow Weald to Oswiecim | 858.00 mi (1,380.82 km) |
| Harrow Weald to Otwock | 919.20 mi (1,479.31 km) |
| Harrow Weald to Ozarow Mazowiecki | 898.81 mi (1,446.49 km) |
| Harrow Weald to Ozimek | 804.66 mi (1,294.97 km) |
| Harrow Weald to Ozorkow | 836.52 mi (1,346.25 km) |
| Harrow Weald to Pabianice | 843.35 mi (1,357.24 km) |
