| Difficult Run to Ridgeland (Mississippi) | 845.33 mi (1,360.42 km) |
| Difficult Run to Ridgewood (New Jersey) | 223.62 mi (359.89 km) |
| Difficult Run to Rifle (Colorado) | 1,621.46 mi (2,609.49 km) |
| Difficult Run to Rincon (Georgia) | 505.93 mi (814.21 km) |
| Difficult Run to Ringwood (New Jersey) | 222.79 mi (358.54 km) |
| Difficult Run to Río Grande (Puerto Rico) | 1,577.14 mi (2,538.16 km) |
| Difficult Run to Rio Grande City (Texas) | 1,513.32 mi (2,435.45 km) |
| Difficult Run to Rio Linda (California) | 2,350.81 mi (3,783.26 km) |
| Difficult Run to Rio Rancho (New Mexico) | 1,629.57 mi (2,622.54 km) |
| Difficult Run to Rio Rico (Arizona) | 1,954.96 mi (3,146.21 km) |
| Difficult Run to Ripon (California) | 2,351.67 mi (3,784.64 km) |
| Difficult Run to River Edge (New Jersey) | 224.30 mi (360.97 km) |
| Difficult Run to River Falls (Wisconsin) | 885.24 mi (1,424.66 km) |
| Difficult Run to River Forest (Illinois) | 588.08 mi (946.43 km) |
| Difficult Run to River Grove (Illinois) | 589.59 mi (948.86 km) |
