| Arcos de Valdevez to Olympia Heights (Florida) | 4,155.48 mi (6,687.60 km) |
| Arcos de Valdevez to Omaha (Nebraska) | 4,312.28 mi (6,939.94 km) |
| Arcos de Valdevez to On Top of the World Designated Place (Florida) | 4,121.06 mi (6,632.21 km) |
| Arcos de Valdevez to Onalaska (Wisconsin) | 4,007.54 mi (6,449.51 km) |
| Arcos de Valdevez to Oneida (New York) | 3,332.48 mi (5,363.11 km) |
| Arcos de Valdevez to Oneonta (New York) | 3,321.51 mi (5,345.45 km) |
| Arcos de Valdevez to Ontario (California) | 5,539.87 mi (8,915.55 km) |
| Arcos de Valdevez to Ontario (Oregon) | 5,040.42 mi (8,111.77 km) |
| Arcos de Valdevez to Opa-locka (Florida) | 4,144.23 mi (6,669.49 km) |
| Arcos de Valdevez to Opelika (Alabama) | 4,138.47 mi (6,660.22 km) |
| Arcos de Valdevez to Opelousas (Louisiana) | 4,547.39 mi (7,318.31 km) |
| Arcos de Valdevez to Orange (California) | 5,560.08 mi (8,948.08 km) |
| Arcos de Valdevez to Orange (Texas) | 4,644.72 mi (7,474.95 km) |
| Arcos de Valdevez to Orange City (Florida) | 4,077.59 mi (6,562.25 km) |
| Arcos de Valdevez to Orangeburg (South Carolina) | 3,886.86 mi (6,255.30 km) |
