| Fort Madison to Odessa (Texas) | 858.87 mi (1,382.22 km) |
| Fort Madison to Ogden (Utah) | 1,074.62 mi (1,729.44 km) |
| Fort Madison to Oildale (California) | 1,541.74 mi (2,481.20 km) |
| Fort Madison to Ojus (Florida) | 1,199.44 mi (1,930.32 km) |
| Fort Madison to Okemos (Michigan) | 385.83 mi (620.93 km) |
| Fort Madison to Oklahoma City (Oklahoma) | 488.84 mi (786.70 km) |
| Fort Madison to Okmulgee (Oklahoma) | 428.51 mi (689.62 km) |
| Fort Madison to Olathe (Kansas) | 219.90 mi (353.90 km) |
| Fort Madison to Old Jamestown (Missouri) | 135.49 mi (218.04 km) |
| Fort Madison to Oldsmar (Florida) | 998.55 mi (1,607.01 km) |
| Fort Madison to Olean (New York) | 676.94 mi (1,089.43 km) |
| Fort Madison to Olive Branch (Mississippi) | 399.56 mi (643.03 km) |
| Fort Madison to Olivehurst (California) | 1,597.92 mi (2,571.60 km) |
| Fort Madison to Olney (Maryland) | 763.03 mi (1,227.98 km) |
| Fort Madison to Olympia (Washington) | 1,621.39 mi (2,609.38 km) |
