| Gretna to Oswego (Illinois) | 819.06 mi (1,318.15 km) |
| Gretna to Oswego (New York) | 1,196.35 mi (1,925.34 km) |
| Gretna to Otsego (Minnesota) | 1,078.53 mi (1,735.73 km) |
| Gretna to Ottawa (Illinois) | 793.76 mi (1,277.44 km) |
| Gretna to Ottawa (Kansas) | 669.80 mi (1,077.94 km) |
| Gretna to Ottumwa (Iowa) | 778.97 mi (1,253.63 km) |
| Gretna to Overland (Missouri) | 607.36 mi (977.45 km) |
| Gretna to Overland Park (Kansas) | 673.93 mi (1,084.59 km) |
| Gretna to Overlea (Maryland) | 1,007.21 mi (1,620.94 km) |
| Gretna to Oviedo (Florida) | 541.01 mi (870.67 km) |
| Gretna to Owasso (Oklahoma) | 552.99 mi (889.95 km) |
| Gretna to Owatonna (Minnesota) | 995.19 mi (1,601.60 km) |
| Gretna to Owensboro (Kentucky) | 567.66 mi (913.56 km) |
| Gretna to Owings Mills (Maryland) | 997.44 mi (1,605.22 km) |
| Gretna to Owosso (Michigan) | 960.62 mi (1,545.96 km) |
