| Delaware to Orangevale (California) | 2,021.40 mi (3,253.13 km) |
| Delaware to Orchards (Washington) | 2,007.82 mi (3,231.27 km) |
| Delaware to Orcutt (California) | 2,063.41 mi (3,320.74 km) |
| Delaware to Oregon (Ohio) | 96.30 mi (154.98 km) |
| Delaware to Oregon (Wisconsin) | 373.65 mi (601.33 km) |
| Delaware to Oregon City (Oregon) | 2,012.43 mi (3,238.70 km) |
| Delaware to Orem (Utah) | 1,501.96 mi (2,417.17 km) |
| Delaware to Orinda (California) | 2,086.85 mi (3,358.46 km) |
| Delaware to Orland Park (Illinois) | 266.00 mi (428.09 km) |
| Delaware to Orlando (Florida) | 821.78 mi (1,322.53 km) |
| Delaware to Ormond Beach (Florida) | 767.25 mi (1,234.76 km) |
| Delaware to Oro Valley (Arizona) | 1,636.81 mi (2,634.19 km) |
| Delaware to Oroville (California) | 2,024.89 mi (3,258.75 km) |
| Delaware to Oshkosh (Wisconsin) | 381.55 mi (614.05 km) |
| Delaware to Oskaloosa (Iowa) | 504.98 mi (812.69 km) |
