| Castle Rock to Oakley (California) | 912.02 mi (1,467.75 km) |
| Castle Rock to Oakton (Virginia) | 1,471.27 mi (2,367.79 km) |
| Castle Rock to Oakville (Missouri) | 783.14 mi (1,260.33 km) |
| Castle Rock to Oatfield (Oregon) | 993.86 mi (1,599.47 km) |
| Castle Rock to Ocala (Florida) | 1,469.30 mi (2,364.61 km) |
| Castle Rock to Ocean Acres (New Jersey) | 1,620.80 mi (2,608.43 km) |
| Castle Rock to Ocean City (New Jersey) | 1,609.31 mi (2,589.93 km) |
| Castle Rock to Ocean Pines (Maryland) | 1,591.96 mi (2,562.01 km) |
| Castle Rock to Ocean Pointe (Hawaii) | 3,353.15 mi (5,396.37 km) |
| Castle Rock to Ocean Springs (Mississippi) | 1,098.70 mi (1,768.19 km) |
| Castle Rock to Oceanside (California) | 812.26 mi (1,307.20 km) |
| Castle Rock to Oceanside (New York) | 1,645.77 mi (2,648.62 km) |
| Castle Rock to Ocoee (Florida) | 1,523.65 mi (2,452.07 km) |
| Castle Rock to Oconomowoc (Wisconsin) | 886.34 mi (1,426.43 km) |
| Castle Rock to Odenton (Maryland) | 1,501.31 mi (2,416.13 km) |
