| Williamsport to Olympia (Washington) | 2,275.37 mi (3,661.86 km) |
| Williamsport to Olympia Heights (Florida) | 1,088.56 mi (1,751.87 km) |
| Williamsport to Omaha (Nebraska) | 985.82 mi (1,586.52 km) |
| Williamsport to On Top of the World Designated Place (Florida) | 888.79 mi (1,430.37 km) |
| Williamsport to Onalaska (Wisconsin) | 742.94 mi (1,195.64 km) |
| Williamsport to Oneida (New York) | 145.14 mi (233.59 km) |
| Williamsport to Oneonta (New York) | 131.65 mi (211.88 km) |
| Williamsport to Ontario (California) | 2,253.35 mi (3,626.41 km) |
| Williamsport to Ontario (Oregon) | 2,019.38 mi (3,249.87 km) |
| Williamsport to Opa-locka (Florida) | 1,075.75 mi (1,731.25 km) |
| Williamsport to Opelika (Alabama) | 749.79 mi (1,206.67 km) |
| Williamsport to Opelousas (Louisiana) | 1,118.32 mi (1,799.77 km) |
| Williamsport to Orange (California) | 2,271.42 mi (3,655.50 km) |
| Williamsport to Orange (Texas) | 1,209.03 mi (1,945.75 km) |
| Williamsport to Orange City (Florida) | 883.20 mi (1,421.38 km) |
