| Port Huron to Olympia (Washington) | 1,973.56 mi (3,176.13 km) |
| Port Huron to Olympia Heights (Florida) | 1,198.31 mi (1,928.50 km) |
| Port Huron to Omaha (Nebraska) | 706.91 mi (1,137.66 km) |
| Port Huron to On Top of the World Designated Place (Florida) | 958.80 mi (1,543.03 km) |
| Port Huron to Onalaska (Wisconsin) | 444.16 mi (714.81 km) |
| Port Huron to Oneida (New York) | 342.24 mi (550.78 km) |
| Port Huron to Oneonta (New York) | 375.88 mi (604.91 km) |
| Port Huron to Ontario (California) | 1,982.60 mi (3,190.69 km) |
| Port Huron to Ontario (Oregon) | 1,719.63 mi (2,767.48 km) |
| Port Huron to Opa-locka (Florida) | 1,186.70 mi (1,909.81 km) |
| Port Huron to Opelika (Alabama) | 730.78 mi (1,176.07 km) |
| Port Huron to Opelousas (Louisiana) | 1,011.18 mi (1,627.34 km) |
| Port Huron to Orange (California) | 2,001.26 mi (3,220.72 km) |
| Port Huron to Orange (Texas) | 1,086.04 mi (1,747.81 km) |
| Port Huron to Orange City (Florida) | 972.68 mi (1,565.37 km) |
