| Potomac to Odenton (Maryland) | 27.10 mi (43.61 km) |
| Potomac to Odessa (Texas) | 1,493.16 mi (2,403.01 km) |
| Potomac to Ogden (Utah) | 1,831.36 mi (2,947.29 km) |
| Potomac to Oildale (California) | 2,294.85 mi (3,693.21 km) |
| Potomac to Ojus (Florida) | 918.46 mi (1,478.12 km) |
| Potomac to Okemos (Michigan) | 455.12 mi (732.44 km) |
| Potomac to Oklahoma City (Oklahoma) | 1,141.62 mi (1,837.26 km) |
| Potomac to Okmulgee (Oklahoma) | 1,058.07 mi (1,702.79 km) |
| Potomac to Olathe (Kansas) | 945.67 mi (1,521.90 km) |
| Potomac to Old Jamestown (Missouri) | 703.12 mi (1,131.56 km) |
| Potomac to Oldsmar (Florida) | 820.08 mi (1,319.80 km) |
| Potomac to Olean (New York) | 221.70 mi (356.78 km) |
| Potomac to Olive Branch (Mississippi) | 751.51 mi (1,209.43 km) |
| Potomac to Olivehurst (California) | 2,356.09 mi (3,791.76 km) |
| Potomac to Olney (Maryland) | 11.27 mi (18.14 km) |
