| Boulder to Rancho Cordova (California) | 860.17 mi (1,384.32 km) |
| Boulder to Rancho Cucamonga (California) | 790.73 mi (1,272.56 km) |
| Boulder to Rancho Mirage (California) | 752.98 mi (1,211.81 km) |
| Boulder to Rancho Palos Verdes (California) | 842.81 mi (1,356.37 km) |
| Boulder to Rancho San Diego (California) | 819.06 mi (1,318.16 km) |
| Boulder to Rancho Santa Margarita (California) | 812.03 mi (1,306.84 km) |
| Boulder to Randallstown (Maryland) | 1,506.67 mi (2,424.75 km) |
| Boulder to Rantoul (Illinois) | 901.57 mi (1,450.94 km) |
| Boulder to Rapid City (South Dakota) | 298.38 mi (480.20 km) |
| Boulder to Ravenna (Ohio) | 1,258.17 mi (2,024.83 km) |
| Boulder to Raymondville (Texas) | 1,029.98 mi (1,657.59 km) |
| Boulder to Raymore (Missouri) | 581.97 mi (936.59 km) |
| Boulder to Raytown (Missouri) | 579.11 mi (931.99 km) |
| Boulder to Reading (Ohio) | 1,106.82 mi (1,781.25 km) |
| Boulder to Reading (Pennsylvania) | 1,541.03 mi (2,480.04 km) |
