| Gloucester to Olympia Heights (Florida) | 4,343.22 mi (6,989.75 km) |
| Gloucester to Omaha (Nebraska) | 4,200.65 mi (6,760.30 km) |
| Gloucester to On Top of the World Designated Place (Florida) | 4,254.92 mi (6,847.63 km) |
| Gloucester to Onalaska (Wisconsin) | 3,897.13 mi (6,271.83 km) |
| Gloucester to Oneida (New York) | 3,333.51 mi (5,364.76 km) |
| Gloucester to Oneonta (New York) | 3,335.82 mi (5,368.48 km) |
| Gloucester to Ontario (California) | 5,335.84 mi (8,587.21 km) |
| Gloucester to Ontario (Oregon) | 4,756.79 mi (7,655.31 km) |
| Gloucester to Opa-locka (Florida) | 4,330.78 mi (6,969.72 km) |
| Gloucester to Opelika (Alabama) | 4,206.39 mi (6,769.53 km) |
| Gloucester to Opelousas (Louisiana) | 4,584.92 mi (7,378.72 km) |
| Gloucester to Orange (California) | 5,356.25 mi (8,620.05 km) |
| Gloucester to Orange (Texas) | 4,672.73 mi (7,520.03 km) |
| Gloucester to Orange City (Florida) | 4,221.70 mi (6,794.17 km) |
| Gloucester to Orangeburg (South Carolina) | 3,980.67 mi (6,406.27 km) |
