| Houston to Noventa Vicentina | 5,520.99 mi (8,885.18 km) |
| Houston to Novi di Modena | 5,509.34 mi (8,866.42 km) |
| Houston to Novi Ligure | 5,425.79 mi (8,731.97 km) |
| Houston to Nuoro | 5,609.34 mi (9,027.36 km) |
| Houston to Occhiobello | 5,536.41 mi (8,909.99 km) |
| Houston to Oderzo | 5,541.43 mi (8,918.07 km) |
| Houston to Oggiono | 5,412.97 mi (8,711.33 km) |
| Houston to Olbia | 5,594.89 mi (9,004.10 km) |
| Houston to Oleggio | 5,389.74 mi (8,673.95 km) |
| Houston to Olgiate Comasco | 5,397.12 mi (8,685.82 km) |
| Houston to Olgiate Olona | 5,398.96 mi (8,688.79 km) |
| Houston to Omegna | 5,370.58 mi (8,643.12 km) |
| Houston to Opera | 5,421.68 mi (8,725.35 km) |
| Houston to Oppeano | 5,506.01 mi (8,861.07 km) |
| Houston to Orbassano | 5,364.40 mi (8,633.17 km) |
