| Norristown to Olympia Heights (Florida) | 1,035.73 mi (1,666.85 km) |
| Norristown to Omaha (Nebraska) | 1,085.39 mi (1,746.77 km) |
| Norristown to On Top of the World Designated Place (Florida) | 856.86 mi (1,378.98 km) |
| Norristown to Onalaska (Wisconsin) | 853.62 mi (1,373.78 km) |
| Norristown to Oneida (New York) | 204.81 mi (329.61 km) |
| Norristown to Oneonta (New York) | 161.79 mi (260.38 km) |
| Norristown to Ontario (California) | 2,344.93 mi (3,773.80 km) |
| Norristown to Ontario (Oregon) | 2,129.43 mi (3,426.98 km) |
| Norristown to Opa-locka (Florida) | 1,022.66 mi (1,645.82 km) |
| Norristown to Opelika (Alabama) | 758.93 mi (1,221.37 km) |
| Norristown to Opelousas (Louisiana) | 1,150.25 mi (1,851.15 km) |
| Norristown to Orange (California) | 2,362.67 mi (3,802.35 km) |
| Norristown to Orange (Texas) | 1,245.45 mi (2,004.36 km) |
| Norristown to Orange City (Florida) | 843.35 mi (1,357.25 km) |
| Norristown to Orangeburg (South Carolina) | 550.47 mi (885.89 km) |
