| Welver to Olympia Heights (Florida) | 4,773.86 mi (7,682.78 km) |
| Welver to Omaha (Nebraska) | 4,572.13 mi (7,358.14 km) |
| Welver to On Top of the World Designated Place (Florida) | 4,679.67 mi (7,531.20 km) |
| Welver to Onalaska (Wisconsin) | 4,271.80 mi (6,874.80 km) |
| Welver to Oneida (New York) | 3,740.92 mi (6,020.42 km) |
| Welver to Oneonta (New York) | 3,745.83 mi (6,028.33 km) |
| Welver to Ontario (California) | 5,664.25 mi (9,115.74 km) |
| Welver to Ontario (Oregon) | 5,057.26 mi (8,138.87 km) |
| Welver to Opa-locka (Florida) | 4,761.33 mi (7,662.62 km) |
| Welver to Opelika (Alabama) | 4,621.11 mi (7,436.97 km) |
| Welver to Opelousas (Louisiana) | 4,991.85 mi (8,033.60 km) |
| Welver to Orange (California) | 5,684.55 mi (9,148.39 km) |
| Welver to Orange (Texas) | 5,077.16 mi (8,170.91 km) |
| Welver to Orange City (Florida) | 4,647.87 mi (7,480.03 km) |
| Welver to Orangeburg (South Carolina) | 4,400.75 mi (7,082.33 km) |
