| Castle Rock to Indianola (Iowa) | 609.39 mi (980.72 km) |
| Castle Rock to Indio (California) | 741.37 mi (1,193.12 km) |
| Castle Rock to Inglewood (California) | 835.00 mi (1,343.80 km) |
| Castle Rock to Inkster (Michigan) | 1,140.65 mi (1,835.70 km) |
| Castle Rock to Inver Grove Heights (Minnesota) | 711.16 mi (1,144.49 km) |
| Castle Rock to Inwood (New York) | 1,639.93 mi (2,639.21 km) |
| Castle Rock to Iona (Florida) | 1,589.89 mi (2,558.67 km) |
| Castle Rock to Ionia (Michigan) | 1,055.66 mi (1,698.92 km) |
| Castle Rock to Iowa City (Iowa) | 716.53 mi (1,153.14 km) |
| Castle Rock to Irmo (South Carolina) | 1,355.23 mi (2,181.03 km) |
| Castle Rock to Irondale (Alabama) | 1,085.86 mi (1,747.52 km) |
| Castle Rock to Ironton (Ohio) | 1,189.93 mi (1,915.01 km) |
| Castle Rock to Irvine (California) | 817.17 mi (1,315.10 km) |
| Castle Rock to Irving (Texas) | 629.10 mi (1,012.44 km) |
| Castle Rock to Isabela (Puerto Rico) | 2,674.92 mi (4,304.86 km) |
