| Boulder to Romeoville (Illinois) | 902.09 mi (1,451.77 km) |
| Boulder to Romulus (Michigan) | 1,145.99 mi (1,844.29 km) |
| Boulder to Ronkonkoma (New York) | 1,681.47 mi (2,706.07 km) |
| Boulder to Roosevelt (New York) | 1,659.04 mi (2,669.97 km) |
| Boulder to Rosamond (California) | 794.34 mi (1,278.37 km) |
| Boulder to Rosaryville (Maryland) | 1,513.81 mi (2,436.24 km) |
| Boulder to Roscoe (Illinois) | 858.88 mi (1,382.24 km) |
| Boulder to Rose Hill (Virginia) | 1,498.68 mi (2,411.89 km) |
| Boulder to Roseburg (Oregon) | 958.51 mi (1,542.57 km) |
| Boulder to Rosedale (California) | 826.08 mi (1,329.46 km) |
| Boulder to Rosedale (Maryland) | 1,522.69 mi (2,450.53 km) |
| Boulder to Roselle (Illinois) | 903.68 mi (1,454.33 km) |
| Boulder to Roselle (New Jersey) | 1,624.31 mi (2,614.07 km) |
| Boulder to Roselle Park (New Jersey) | 1,623.83 mi (2,613.30 km) |
| Boulder to Rosemead (California) | 817.28 mi (1,315.29 km) |
