| Difficult Run to Hutchinson (Minnesota) | 966.01 mi (1,554.65 km) |
| Difficult Run to Hutto (Texas) | 1,280.32 mi (2,060.48 km) |
| Difficult Run to Hyattsville (Maryland) | 21.48 mi (34.58 km) |
| Difficult Run to Hybla Valley (Virginia) | 17.76 mi (28.59 km) |
| Difficult Run to Idaho Falls (Idaho) | 1,817.58 mi (2,925.12 km) |
| Difficult Run to Idylwood (Virginia) | 7.65 mi (12.32 km) |
| Difficult Run to Ilchester (Maryland) | 38.00 mi (61.16 km) |
| Difficult Run to Immokalee (Florida) | 893.79 mi (1,438.41 km) |
| Difficult Run to Imperial (California) | 2,164.51 mi (3,483.44 km) |
| Difficult Run to Imperial Beach (California) | 2,254.72 mi (3,628.62 km) |
| Difficult Run to Independence (Kentucky) | 387.04 mi (622.88 km) |
| Difficult Run to Independence (Missouri) | 911.81 mi (1,467.42 km) |
| Difficult Run to Indian Trail (North Carolina) | 321.23 mi (516.96 km) |
| Difficult Run to Indiana (Pennsylvania) | 152.81 mi (245.92 km) |
| Difficult Run to Indianapolis (Indiana) | 473.85 mi (762.59 km) |
