| Castle Rock to Odessa (Texas) | 536.69 mi (863.72 km) |
| Castle Rock to Ogden (Utah) | 395.98 mi (637.27 km) |
| Castle Rock to Oildale (California) | 823.44 mi (1,325.21 km) |
| Castle Rock to Ojus (Florida) | 1,700.59 mi (2,736.83 km) |
| Castle Rock to Okemos (Michigan) | 1,086.87 mi (1,749.15 km) |
| Castle Rock to Oklahoma City (Oklahoma) | 484.66 mi (779.98 km) |
| Castle Rock to Okmulgee (Oklahoma) | 549.89 mi (884.97 km) |
| Castle Rock to Olathe (Kansas) | 538.56 mi (866.74 km) |
| Castle Rock to Old Jamestown (Missouri) | 781.12 mi (1,257.09 km) |
| Castle Rock to Oldsmar (Florida) | 1,489.69 mi (2,397.43 km) |
| Castle Rock to Olean (New York) | 1,390.33 mi (2,237.53 km) |
| Castle Rock to Olive Branch (Mississippi) | 879.41 mi (1,415.28 km) |
| Castle Rock to Olivehurst (California) | 892.95 mi (1,437.06 km) |
| Castle Rock to Olney (Maryland) | 1,480.42 mi (2,382.50 km) |
| Castle Rock to Olympia (Washington) | 1,048.03 mi (1,686.64 km) |
