| Delaware to Oakley (California) | 2,059.38 mi (3,314.24 km) |
| Delaware to Oakton (Virginia) | 322.08 mi (518.35 km) |
| Delaware to Oakville (Missouri) | 407.18 mi (655.30 km) |
| Delaware to Oatfield (Oregon) | 2,012.16 mi (3,238.25 km) |
| Delaware to Ocala (Florida) | 769.20 mi (1,237.91 km) |
| Delaware to Ocean Acres (New Jersey) | 466.65 mi (751.00 km) |
| Delaware to Ocean City (New Jersey) | 455.15 mi (732.49 km) |
| Delaware to Ocean Pines (Maryland) | 443.23 mi (713.31 km) |
| Delaware to Ocean Pointe (Hawaii) | 4,504.67 mi (7,249.57 km) |
| Delaware to Ocean Springs (Mississippi) | 754.10 mi (1,213.60 km) |
| Delaware to Oceanside (California) | 1,943.79 mi (3,128.22 km) |
| Delaware to Oceanside (New York) | 496.49 mi (799.03 km) |
| Delaware to Ocoee (Florida) | 813.48 mi (1,309.18 km) |
| Delaware to Oconomowoc (Wisconsin) | 340.52 mi (548.02 km) |
| Delaware to Odenton (Maryland) | 349.51 mi (562.48 km) |
