| Omagh to Olympia Heights (Florida) | 4,118.37 mi (6,627.88 km) |
| Omagh to Omaha (Nebraska) | 3,927.52 mi (6,320.74 km) |
| Omagh to On Top of the World Designated Place (Florida) | 4,018.67 mi (6,467.42 km) |
| Omagh to Onalaska (Wisconsin) | 3,624.87 mi (5,833.66 km) |
| Omagh to Oneida (New York) | 3,078.10 mi (4,953.72 km) |
| Omagh to Oneonta (New York) | 3,082.60 mi (4,960.96 km) |
| Omagh to Ontario (California) | 5,055.64 mi (8,136.26 km) |
| Omagh to Ontario (Oregon) | 4,475.91 mi (7,203.28 km) |
| Omagh to Opa-locka (Florida) | 4,105.73 mi (6,607.53 km) |
| Omagh to Opelika (Alabama) | 3,957.63 mi (6,369.19 km) |
| Omagh to Opelousas (Louisiana) | 4,329.36 mi (6,967.43 km) |
| Omagh to Orange (California) | 5,076.04 mi (8,169.10 km) |
| Omagh to Orange (Texas) | 4,415.35 mi (7,105.81 km) |
| Omagh to Orange City (Florida) | 3,987.81 mi (6,417.76 km) |
| Omagh to Orangeburg (South Carolina) | 3,737.94 mi (6,015.63 km) |
