| Sintra to Oswego (Illinois) | 4,015.15 mi (6,461.76 km) |
| Sintra to Oswego (New York) | 3,412.15 mi (5,491.32 km) |
| Sintra to Otsego (Minnesota) | 4,144.46 mi (6,669.87 km) |
| Sintra to Ottawa (Illinois) | 4,047.80 mi (6,514.31 km) |
| Sintra to Ottawa (Kansas) | 4,438.02 mi (7,142.30 km) |
| Sintra to Ottumwa (Iowa) | 4,224.71 mi (6,799.02 km) |
| Sintra to Overland (Missouri) | 4,204.32 mi (6,766.20 km) |
| Sintra to Overland Park (Kansas) | 4,401.17 mi (7,083.01 km) |
| Sintra to Overlea (Maryland) | 3,512.17 mi (5,652.28 km) |
| Sintra to Oviedo (Florida) | 4,080.78 mi (6,567.38 km) |
| Sintra to Owasso (Oklahoma) | 4,546.79 mi (7,317.34 km) |
| Sintra to Owatonna (Minnesota) | 4,163.76 mi (6,700.93 km) |
| Sintra to Owensboro (Kentucky) | 4,078.38 mi (6,563.51 km) |
| Sintra to Owings Mills (Maryland) | 3,524.47 mi (5,672.09 km) |
| Sintra to Owosso (Michigan) | 3,784.19 mi (6,090.07 km) |
