| Boulder to Rockville (Maryland) | 1,492.01 mi (2,401.16 km) |
| Boulder to Rockville Centre (New York) | 1,656.38 mi (2,665.69 km) |
| Boulder to Rockwall (Texas) | 692.89 mi (1,115.09 km) |
| Boulder to Rocky Mount (North Carolina) | 1,514.32 mi (2,437.06 km) |
| Boulder to Rocky Point (New York) | 1,689.82 mi (2,719.50 km) |
| Boulder to Rocky River (Ohio) | 1,225.17 mi (1,971.72 km) |
| Boulder to Roessleville (New York) | 1,632.17 mi (2,626.72 km) |
| Boulder to Rogers (Arkansas) | 654.47 mi (1,053.26 km) |
| Boulder to Rogers (Minnesota) | 691.55 mi (1,112.95 km) |
| Boulder to Rohnert Park (California) | 939.82 mi (1,512.49 km) |
| Boulder to Rolla (Missouri) | 737.93 mi (1,187.58 km) |
| Boulder to Rolling Meadows (Illinois) | 907.14 mi (1,459.91 km) |
| Boulder to Roma (Texas) | 1,006.45 mi (1,619.73 km) |
| Boulder to Rome (Georgia) | 1,171.43 mi (1,885.23 km) |
| Boulder to Rome (New York) | 1,544.62 mi (2,485.82 km) |
