| Sumter to Olympia (Washington) | 2,374.71 mi (3,821.73 km) |
| Sumter to Olympia Heights (Florida) | 567.62 mi (913.50 km) |
| Sumter to Omaha (Nebraska) | 993.18 mi (1,598.37 km) |
| Sumter to On Top of the World Designated Place (Florida) | 352.06 mi (566.59 km) |
| Sumter to Onalaska (Wisconsin) | 898.70 mi (1,446.31 km) |
| Sumter to Oneida (New York) | 680.89 mi (1,095.79 km) |
| Sumter to Oneonta (New York) | 655.28 mi (1,054.57 km) |
| Sumter to Ontario (California) | 2,119.86 mi (3,411.59 km) |
| Sumter to Ontario (Oregon) | 2,064.87 mi (3,323.09 km) |
| Sumter to Opa-locka (Florida) | 555.54 mi (894.05 km) |
| Sumter to Opelika (Alabama) | 301.01 mi (484.44 km) |
| Sumter to Opelousas (Louisiana) | 722.20 mi (1,162.26 km) |
| Sumter to Orange (California) | 2,135.02 mi (3,435.98 km) |
| Sumter to Orange (Texas) | 825.45 mi (1,328.43 km) |
| Sumter to Orange City (Florida) | 349.77 mi (562.90 km) |
