| Hartford to Opole | 4,099.20 mi (6,597.03 km) |
| Hartford to Orzesze | 4,148.25 mi (6,675.97 km) |
| Hartford to Osowa | 3,992.81 mi (6,425.81 km) |
| Hartford to Ostroda | 4,070.19 mi (6,550.33 km) |
| Hartford to Ostroleka | 4,149.18 mi (6,677.46 km) |
| Hartford to Ostrow Mazowiecka | 4,170.58 mi (6,711.89 km) |
| Hartford to Ostrow Wielkopolski | 4,061.28 mi (6,536.00 km) |
| Hartford to Ostrowiec Swietokrzyski | 4,219.76 mi (6,791.05 km) |
| Hartford to Ostrzeszow | 4,073.55 mi (6,555.74 km) |
| Hartford to Oswiecim | 4,170.16 mi (6,711.23 km) |
| Hartford to Otwock | 4,172.20 mi (6,714.50 km) |
| Hartford to Ozarow Mazowiecki | 4,151.68 mi (6,681.49 km) |
| Hartford to Ozimek | 4,109.60 mi (6,613.76 km) |
| Hartford to Ozorkow | 4,104.90 mi (6,606.19 km) |
| Hartford to Pabianice | 4,119.57 mi (6,629.81 km) |
