| Potomac to Marrero (Louisiana) | 967.42 mi (1,556.91 km) |
| Potomac to Marshall (Minnesota) | 1,026.85 mi (1,652.55 km) |
| Potomac to Marshall (Missouri) | 857.62 mi (1,380.21 km) |
| Potomac to Marshall (Texas) | 1,058.48 mi (1,703.46 km) |
| Potomac to Marshalltown (Iowa) | 849.84 mi (1,367.68 km) |
| Potomac to Marshfield (Wisconsin) | 772.38 mi (1,243.03 km) |
| Potomac to Martha Lake (Washington) | 2,305.44 mi (3,710.24 km) |
| Potomac to Martin (Tennessee) | 663.19 mi (1,067.29 km) |
| Potomac to Martinez (California) | 2,404.80 mi (3,870.16 km) |
| Potomac to Martinez (Georgia) | 467.47 mi (752.32 km) |
| Potomac to Martinsburg (West Virginia) | 51.95 mi (83.60 km) |
| Potomac to Martinsville (Indiana) | 495.05 mi (796.71 km) |
| Potomac to Martinsville (New Jersey) | 177.12 mi (285.05 km) |
| Potomac to Martinsville (Virginia) | 217.14 mi (349.45 km) |
| Potomac to Maryland City (Maryland) | 21.74 mi (34.99 km) |
