| Castle Rock to Mauldin (South Carolina) | 1,279.20 mi (2,058.67 km) |
| Castle Rock to Maumee (Ohio) | 1,121.12 mi (1,804.27 km) |
| Castle Rock to Maumelle (Arkansas) | 753.11 mi (1,212.01 km) |
| Castle Rock to Mayagüez (Puerto Rico) | 2,682.59 mi (4,317.21 km) |
| Castle Rock to Mayfield Heights (Ohio) | 1,235.42 mi (1,988.22 km) |
| Castle Rock to Mays Chapel (Maryland) | 1,499.40 mi (2,413.06 km) |
| Castle Rock to Maywood (California) | 826.14 mi (1,329.55 km) |
| Castle Rock to Maywood (Illinois) | 906.97 mi (1,459.62 km) |
| Castle Rock to McAlester (Oklahoma) | 586.58 mi (944.01 km) |
| Castle Rock to McAllen (Texas) | 985.58 mi (1,586.14 km) |
| Castle Rock to McCalla (Alabama) | 1,074.67 mi (1,729.52 km) |
| Castle Rock to McComb (Mississippi) | 984.54 mi (1,584.46 km) |
| Castle Rock to McDonough (Georgia) | 1,218.75 mi (1,961.38 km) |
| Castle Rock to McFarland (California) | 827.66 mi (1,332.00 km) |
| Castle Rock to McHenry (Illinois) | 887.72 mi (1,428.64 km) |
