| Gretna to Portage (Michigan) | 884.60 mi (1,423.63 km) |
| Gretna to Portage (Wisconsin) | 942.90 mi (1,517.45 km) |
| Gretna to Portales (New Mexico) | 832.27 mi (1,339.41 km) |
| Gretna to Porterville (California) | 1,725.63 mi (2,777.14 km) |
| Gretna to Portland (Maine) | 1,443.19 mi (2,322.58 km) |
| Gretna to Portland (Oregon) | 2,061.98 mi (3,318.44 km) |
| Gretna to Portland (Tennessee) | 504.56 mi (812.02 km) |
| Gretna to Portland (Texas) | 461.53 mi (742.76 km) |
| Gretna to Portsmouth (New Hampshire) | 1,397.82 mi (2,249.58 km) |
| Gretna to Portsmouth (Ohio) | 732.77 mi (1,179.27 km) |
| Gretna to Portsmouth (Virginia) | 922.83 mi (1,485.16 km) |
| Gretna to Post Falls (Idaho) | 1,882.65 mi (3,029.84 km) |
| Gretna to Potomac (Maryland) | 963.69 mi (1,550.90 km) |
| Gretna to Potomac Park (California) | 1,717.43 mi (2,763.94 km) |
| Gretna to Pottstown (Pennsylvania) | 1,080.93 mi (1,739.59 km) |
