| Ottawa to Orangeburg (South Carolina) | 696.36 mi (1,120.68 km) |
| Ottawa to Orangevale (California) | 1,713.91 mi (2,758.27 km) |
| Ottawa to Orchards (Washington) | 1,701.91 mi (2,738.96 km) |
| Ottawa to Orcutt (California) | 1,764.45 mi (2,839.61 km) |
| Ottawa to Oregon (Ohio) | 279.82 mi (450.32 km) |
| Ottawa to Oregon (Wisconsin) | 112.23 mi (180.62 km) |
| Ottawa to Oregon City (Oregon) | 1,705.91 mi (2,745.40 km) |
| Ottawa to Orem (Utah) | 1,194.62 mi (1,922.56 km) |
| Ottawa to Orinda (California) | 1,780.20 mi (2,864.95 km) |
| Ottawa to Orland Park (Illinois) | 52.86 mi (85.07 km) |
| Ottawa to Orlando (Florida) | 984.79 mi (1,584.87 km) |
| Ottawa to Ormond Beach (Florida) | 939.01 mi (1,511.20 km) |
| Ottawa to Oro Valley (Arizona) | 1,365.46 mi (2,197.50 km) |
| Ottawa to Oroville (California) | 1,716.37 mi (2,762.23 km) |
| Ottawa to Oshkosh (Wisconsin) | 184.77 mi (297.36 km) |
