| Gretna to Odessa (Texas) | 741.03 mi (1,192.57 km) |
| Gretna to Ogden (Utah) | 1,452.53 mi (2,337.63 km) |
| Gretna to Oildale (California) | 1,721.47 mi (2,770.44 km) |
| Gretna to Ojus (Florida) | 662.35 mi (1,065.95 km) |
| Gretna to Okemos (Michigan) | 937.58 mi (1,508.89 km) |
| Gretna to Oklahoma City (Oklahoma) | 579.07 mi (931.93 km) |
| Gretna to Okmulgee (Oklahoma) | 524.17 mi (843.58 km) |
| Gretna to Olathe (Kansas) | 676.70 mi (1,089.04 km) |
| Gretna to Old Jamestown (Missouri) | 617.10 mi (993.12 km) |
| Gretna to Oldsmar (Florida) | 464.19 mi (747.04 km) |
| Gretna to Olean (New York) | 1,060.44 mi (1,706.62 km) |
| Gretna to Olive Branch (Mississippi) | 349.19 mi (561.96 km) |
| Gretna to Olivehurst (California) | 1,891.27 mi (3,043.70 km) |
| Gretna to Olney (Maryland) | 974.45 mi (1,568.22 km) |
| Gretna to Olympia (Washington) | 2,110.65 mi (3,396.76 km) |
