| Pembroke Dock to Olympia Heights (Florida) | 4,230.01 mi (6,807.54 km) |
| Pembroke Dock to Omaha (Nebraska) | 4,106.54 mi (6,608.84 km) |
| Pembroke Dock to On Top of the World Designated Place (Florida) | 4,143.81 mi (6,668.83 km) |
| Pembroke Dock to Onalaska (Wisconsin) | 3,802.31 mi (6,119.22 km) |
| Pembroke Dock to Oneida (New York) | 3,228.59 mi (5,195.91 km) |
| Pembroke Dock to Oneonta (New York) | 3,230.02 mi (5,198.22 km) |
| Pembroke Dock to Ontario (California) | 5,253.43 mi (8,454.58 km) |
| Pembroke Dock to Ontario (Oregon) | 4,683.10 mi (7,536.72 km) |
| Pembroke Dock to Opa-locka (Florida) | 4,217.60 mi (6,787.57 km) |
| Pembroke Dock to Opelika (Alabama) | 4,098.67 mi (6,596.17 km) |
| Pembroke Dock to Opelousas (Louisiana) | 4,479.58 mi (7,209.19 km) |
| Pembroke Dock to Orange (California) | 5,273.85 mi (8,487.44 km) |
| Pembroke Dock to Orange (Texas) | 4,568.14 mi (7,351.71 km) |
| Pembroke Dock to Orange City (Florida) | 4,110.10 mi (6,614.57 km) |
| Pembroke Dock to Orangeburg (South Carolina) | 3,871.23 mi (6,230.14 km) |
