| Houston to Oerlinghausen | 5,171.35 mi (8,322.49 km) |
| Houston to Oestrich-Winkel | 5,212.51 mi (8,388.73 km) |
| Houston to Offenburg | 5,261.93 mi (8,468.26 km) |
| Houston to Oftersheim | 5,256.69 mi (8,459.83 km) |
| Houston to Ohrdruf | 5,287.87 mi (8,510.00 km) |
| Houston to Ohringen | 5,298.29 mi (8,526.77 km) |
| Houston to Olbernhau | 5,390.27 mi (8,674.80 km) |
| Houston to Olching | 5,404.93 mi (8,698.39 km) |
| Houston to Oldenburg | 5,115.31 mi (8,232.29 km) |
| Houston to Oldenburg in Holstein | 5,170.97 mi (8,321.87 km) |
| Houston to Olfen | 5,131.71 mi (8,258.69 km) |
| Houston to Olpe | 5,171.95 mi (8,323.45 km) |
| Houston to Olsberg | 5,185.34 mi (8,345.00 km) |
| Houston to Oranienburg | 5,309.07 mi (8,544.13 km) |
| Houston to Ortenberg | 5,240.97 mi (8,434.53 km) |
