| Round Lake to Oerlinghausen | 4,250.68 mi (6,840.81 km) |
| Round Lake to Oestrich-Winkel | 4,301.78 mi (6,923.05 km) |
| Round Lake to Offenburg | 4,358.80 mi (7,014.81 km) |
| Round Lake to Oftersheim | 4,347.83 mi (6,997.15 km) |
| Round Lake to Ohrdruf | 4,368.57 mi (7,030.53 km) |
| Round Lake to Ohringen | 4,388.44 mi (7,062.51 km) |
| Round Lake to Olbernhau | 4,467.18 mi (7,189.23 km) |
| Round Lake to Olching | 4,496.04 mi (7,235.67 km) |
| Round Lake to Oldenburg | 4,190.45 mi (6,743.88 km) |
| Round Lake to Oldenburg in Holstein | 4,238.20 mi (6,820.72 km) |
| Round Lake to Olfen | 4,214.18 mi (6,782.07 km) |
| Round Lake to Olpe | 4,256.81 mi (6,850.68 km) |
| Round Lake to Olsberg | 4,267.62 mi (6,868.07 km) |
| Round Lake to Oranienburg | 4,378.50 mi (7,046.51 km) |
| Round Lake to Ortenberg | 4,326.67 mi (6,963.10 km) |
