| Castle Rock to Ukiah (California) | 980.47 mi (1,577.92 km) |
| Castle Rock to Union (Missouri) | 747.29 mi (1,202.65 km) |
| Castle Rock to Union City (California) | 934.88 mi (1,504.54 km) |
| Castle Rock to Union City (Georgia) | 1,192.71 mi (1,919.48 km) |
| Castle Rock to Union City (New Jersey) | 1,624.05 mi (2,613.66 km) |
| Castle Rock to Union City (Tennessee) | 884.24 mi (1,423.05 km) |
| Castle Rock to Union Hill-Novelty Hill (Washington) | 1,030.48 mi (1,658.40 km) |
| Castle Rock to Union Park (Florida) | 1,538.94 mi (2,476.69 km) |
| Castle Rock to Uniondale (New York) | 1,647.21 mi (2,650.93 km) |
| Castle Rock to Universal City (Texas) | 773.91 mi (1,245.49 km) |
| Castle Rock to University (Florida) | 1,500.05 mi (2,414.09 km) |
| Castle Rock to University City (Missouri) | 780.24 mi (1,255.67 km) |
| Castle Rock to University Heights (Ohio) | 1,231.22 mi (1,981.46 km) |
| Castle Rock to University of California-Santa Barbara (California) | 895.66 mi (1,441.42 km) |
| Castle Rock to University Park (Texas) | 636.39 mi (1,024.18 km) |
