| Potomac to Orangeburg (South Carolina) | 432.80 mi (696.53 km) |
| Potomac to Orangevale (California) | 2,345.39 mi (3,774.55 km) |
| Potomac to Orchards (Washington) | 2,328.20 mi (3,746.87 km) |
| Potomac to Orcutt (California) | 2,381.86 mi (3,833.24 km) |
| Potomac to Oregon (Ohio) | 375.58 mi (604.44 km) |
| Potomac to Oregon (Wisconsin) | 690.37 mi (1,111.04 km) |
| Potomac to Oregon City (Oregon) | 2,333.41 mi (3,755.25 km) |
| Potomac to Orem (Utah) | 1,825.99 mi (2,938.64 km) |
| Potomac to Orinda (California) | 2,410.35 mi (3,879.08 km) |
| Potomac to Orland Park (Illinois) | 589.45 mi (948.62 km) |
| Potomac to Orlando (Florida) | 765.69 mi (1,232.26 km) |
| Potomac to Ormond Beach (Florida) | 707.27 mi (1,138.24 km) |
| Potomac to Oro Valley (Arizona) | 1,937.17 mi (3,117.58 km) |
| Potomac to Oroville (California) | 2,349.41 mi (3,781.02 km) |
| Potomac to Oshkosh (Wisconsin) | 681.44 mi (1,096.67 km) |
