| Slidell to Orbetello | 5,345.14 mi (8,602.18 km) |
| Slidell to Oria | 5,698.20 mi (9,170.37 km) |
| Slidell to Oristano | 5,311.50 mi (8,548.03 km) |
| Slidell to Orta Nova | 5,582.81 mi (8,984.66 km) |
| Slidell to Orte | 5,396.22 mi (8,684.37 km) |
| Slidell to Ortona | 5,488.21 mi (8,832.42 km) |
| Slidell to Orvieto | 5,375.11 mi (8,650.41 km) |
| Slidell to Orzinuovi | 5,190.30 mi (8,352.99 km) |
| Slidell to Osimo | 5,407.94 mi (8,703.24 km) |
| Slidell to Ospitaletto | 5,191.19 mi (8,354.41 km) |
| Slidell to Ostuni | 5,687.06 mi (9,152.45 km) |
| Slidell to Ottaviano | 5,546.15 mi (8,925.67 km) |
| Slidell to Ovada | 5,159.45 mi (8,303.33 km) |
| Slidell to Ozieri | 5,307.98 mi (8,542.36 km) |
| Slidell to Paceco | 5,562.09 mi (8,951.31 km) |
