| Havre de Grace to Oswego (Illinois) | 657.19 mi (1,057.65 km) |
| Havre de Grace to Oswego (New York) | 270.45 mi (435.25 km) |
| Havre de Grace to Otsego (Minnesota) | 973.91 mi (1,567.36 km) |
| Havre de Grace to Ottawa (Illinois) | 679.24 mi (1,093.13 km) |
| Havre de Grace to Ottawa (Kansas) | 1,027.29 mi (1,653.26 km) |
| Havre de Grace to Ottumwa (Iowa) | 864.06 mi (1,390.57 km) |
| Havre de Grace to Overland (Missouri) | 765.52 mi (1,231.99 km) |
| Havre de Grace to Overland Park (Kansas) | 993.47 mi (1,598.83 km) |
| Havre de Grace to Overlea (Maryland) | 24.97 mi (40.18 km) |
| Havre de Grace to Oviedo (Florida) | 806.07 mi (1,297.24 km) |
| Havre de Grace to Owasso (Oklahoma) | 1,095.67 mi (1,763.31 km) |
| Havre de Grace to Owatonna (Minnesota) | 933.47 mi (1,502.28 km) |
| Havre de Grace to Owensboro (Kentucky) | 606.01 mi (975.29 km) |
| Havre de Grace to Owings Mills (Maryland) | 37.30 mi (60.03 km) |
| Havre de Grace to Owosso (Michigan) | 481.34 mi (774.64 km) |
