| Mason City to Orangevale (California) | 1,487.72 mi (2,394.25 km) |
| Mason City to Orchards (Washington) | 1,449.83 mi (2,333.27 km) |
| Mason City to Orcutt (California) | 1,560.84 mi (2,511.93 km) |
| Mason City to Oregon (Ohio) | 508.65 mi (818.60 km) |
| Mason City to Oregon (Wisconsin) | 193.04 mi (310.66 km) |
| Mason City to Oregon City (Oregon) | 1,454.52 mi (2,340.83 km) |
| Mason City to Orem (Utah) | 971.99 mi (1,564.27 km) |
| Mason City to Orinda (California) | 1,556.70 mi (2,505.26 km) |
| Mason City to Orland Park (Illinois) | 292.44 mi (470.64 km) |
| Mason City to Orlando (Florida) | 1,209.38 mi (1,946.31 km) |
| Mason City to Ormond Beach (Florida) | 1,167.95 mi (1,879.64 km) |
| Mason City to Oro Valley (Arizona) | 1,217.02 mi (1,958.60 km) |
| Mason City to Oroville (California) | 1,485.82 mi (2,391.19 km) |
| Mason City to Oshkosh (Wisconsin) | 239.80 mi (385.92 km) |
| Mason City to Oskaloosa (Iowa) | 131.42 mi (211.51 km) |
