| Estoril to Olympia Heights (Florida) | 4,141.11 mi (6,664.47 km) |
| Estoril to Omaha (Nebraska) | 4,385.54 mi (7,057.84 km) |
| Estoril to On Top of the World Designated Place (Florida) | 4,123.70 mi (6,636.46 km) |
| Estoril to Onalaska (Wisconsin) | 4,083.05 mi (6,571.04 km) |
| Estoril to Oneida (New York) | 3,383.18 mi (5,444.70 km) |
| Estoril to Oneonta (New York) | 3,368.47 mi (5,421.02 km) |
| Estoril to Ontario (California) | 5,630.52 mi (9,061.45 km) |
| Estoril to Ontario (Oregon) | 5,156.17 mi (8,298.05 km) |
| Estoril to Opa-locka (Florida) | 4,130.33 mi (6,647.12 km) |
| Estoril to Opelika (Alabama) | 4,160.97 mi (6,696.43 km) |
| Estoril to Opelousas (Louisiana) | 4,575.42 mi (7,363.43 km) |
| Estoril to Orange (California) | 5,650.55 mi (9,093.69 km) |
| Estoril to Orange (Texas) | 4,674.79 mi (7,523.35 km) |
| Estoril to Orange City (Florida) | 4,077.48 mi (6,562.07 km) |
| Estoril to Orangeburg (South Carolina) | 3,903.95 mi (6,282.79 km) |
