| Greenock to Oswego (Illinois) | 3,681.76 mi (5,925.22 km) |
| Greenock to Oswego (New York) | 3,164.18 mi (5,092.25 km) |
| Greenock to Otsego (Minnesota) | 3,688.42 mi (5,935.94 km) |
| Greenock to Ottawa (Illinois) | 3,715.61 mi (5,979.70 km) |
| Greenock to Ottawa (Kansas) | 4,085.44 mi (6,574.88 km) |
| Greenock to Ottumwa (Iowa) | 3,860.18 mi (6,212.36 km) |
| Greenock to Overland (Missouri) | 3,905.84 mi (6,285.83 km) |
| Greenock to Overland Park (Kansas) | 4,050.09 mi (6,518.00 km) |
| Greenock to Overlea (Maryland) | 3,359.30 mi (5,406.28 km) |
| Greenock to Oviedo (Florida) | 4,087.28 mi (6,577.85 km) |
| Greenock to Owasso (Oklahoma) | 4,227.52 mi (6,803.54 km) |
| Greenock to Owatonna (Minnesota) | 3,733.55 mi (6,008.58 km) |
| Greenock to Owensboro (Kentucky) | 3,835.43 mi (6,172.52 km) |
| Greenock to Owings Mills (Maryland) | 3,367.36 mi (5,419.24 km) |
| Greenock to Owosso (Michigan) | 3,467.62 mi (5,580.59 km) |
