| Sleaford to Orbetello | 905.36 mi (1,457.03 km) |
| Sleaford to Oria | 1,208.08 mi (1,944.22 km) |
| Sleaford to Oristano | 999.05 mi (1,607.82 km) |
| Sleaford to Orta Nova | 1,101.11 mi (1,772.06 km) |
| Sleaford to Orte | 937.19 mi (1,508.25 km) |
| Sleaford to Ortona | 1,004.12 mi (1,615.97 km) |
| Sleaford to Orvieto | 914.54 mi (1,471.81 km) |
| Sleaford to Orzinuovi | 701.22 mi (1,128.50 km) |
| Sleaford to Osimo | 913.96 mi (1,470.88 km) |
| Sleaford to Ospitaletto | 697.00 mi (1,121.71 km) |
| Sleaford to Ostuni | 1,193.84 mi (1,921.30 km) |
| Sleaford to Ottaviano | 1,090.10 mi (1,754.35 km) |
| Sleaford to Ovada | 708.22 mi (1,139.78 km) |
| Sleaford to Ozieri | 964.42 mi (1,552.09 km) |
| Sleaford to Paceco | 1,208.32 mi (1,944.60 km) |
