| Boulder to Reidsville (North Carolina) | 1,407.38 mi (2,264.97 km) |
| Boulder to Reisterstown (Maryland) | 1,504.99 mi (2,422.05 km) |
| Boulder to Rendon (Texas) | 680.54 mi (1,095.22 km) |
| Boulder to Reno (Nevada) | 774.77 mi (1,246.87 km) |
| Boulder to Renton (Washington) | 986.76 mi (1,588.04 km) |
| Boulder to Republic (Missouri) | 667.44 mi (1,074.14 km) |
| Boulder to Reston (Virginia) | 1,483.84 mi (2,388.01 km) |
| Boulder to Revere (Massachusetts) | 1,775.44 mi (2,857.30 km) |
| Boulder to Rexburg (Idaho) | 426.24 mi (685.96 km) |
| Boulder to Reynoldsburg (Ohio) | 1,185.66 mi (1,908.13 km) |
| Boulder to Rialto (California) | 782.67 mi (1,259.59 km) |
| Boulder to Richardson (Texas) | 679.52 mi (1,093.58 km) |
| Boulder to Richfield (Minnesota) | 695.22 mi (1,118.85 km) |
| Boulder to Richfield (Wisconsin) | 904.35 mi (1,455.40 km) |
| Boulder to Richland (Washington) | 827.57 mi (1,331.85 km) |
