| Herndon to Oakley (California) | 2,373.46 mi (3,819.72 km) |
| Herndon to Oakton (Virginia) | 7.24 mi (11.65 km) |
| Herndon to Oakville (Missouri) | 697.65 mi (1,122.76 km) |
| Herndon to Oatfield (Oregon) | 2,325.06 mi (3,741.82 km) |
| Herndon to Ocala (Florida) | 729.13 mi (1,173.42 km) |
| Herndon to Ocean Acres (New Jersey) | 174.32 mi (280.54 km) |
| Herndon to Ocean City (New Jersey) | 150.68 mi (242.50 km) |
| Herndon to Ocean Pines (Maryland) | 127.29 mi (204.86 km) |
| Herndon to Ocean Pointe (Hawaii) | 4,818.18 mi (7,754.12 km) |
| Herndon to Ocean Springs (Mississippi) | 875.79 mi (1,409.44 km) |
| Herndon to Oceanside (California) | 2,245.56 mi (3,613.87 km) |
| Herndon to Oceanside (New York) | 229.82 mi (369.86 km) |
| Herndon to Ocoee (Florida) | 756.12 mi (1,216.86 km) |
| Herndon to Oconomowoc (Wisconsin) | 644.71 mi (1,037.56 km) |
| Herndon to Odenton (Maryland) | 37.79 mi (60.81 km) |
