| Castle Rock to Orangevale (California) | 878.54 mi (1,413.87 km) |
| Castle Rock to Orchards (Washington) | 997.21 mi (1,604.86 km) |
| Castle Rock to Orcutt (California) | 911.01 mi (1,466.13 km) |
| Castle Rock to Oregon (Ohio) | 1,133.16 mi (1,823.65 km) |
| Castle Rock to Oregon (Wisconsin) | 839.66 mi (1,351.31 km) |
| Castle Rock to Oregon City (Oregon) | 992.25 mi (1,596.87 km) |
| Castle Rock to Orem (Utah) | 368.65 mi (593.28 km) |
| Castle Rock to Orinda (California) | 939.39 mi (1,511.81 km) |
| Castle Rock to Orland Park (Illinois) | 904.50 mi (1,455.65 km) |
| Castle Rock to Orlando (Florida) | 1,537.45 mi (2,474.28 km) |
| Castle Rock to Ormond Beach (Florida) | 1,517.01 mi (2,441.40 km) |
| Castle Rock to Oro Valley (Arizona) | 589.91 mi (949.37 km) |
| Castle Rock to Oroville (California) | 890.43 mi (1,433.00 km) |
| Castle Rock to Oshkosh (Wisconsin) | 897.78 mi (1,444.83 km) |
| Castle Rock to Oskaloosa (Iowa) | 656.13 mi (1,055.94 km) |
