| Difficult Run to Ickenham | 3,663.33 mi (5,895.56 km) |
| Difficult Run to Ifield | 3,682.79 mi (5,926.88 km) |
| Difficult Run to Ilford | 3,685.09 mi (5,930.59 km) |
| Difficult Run to Ilfracombe | 3,519.45 mi (5,664.01 km) |
| Difficult Run to Ilkeston | 3,599.10 mi (5,792.19 km) |
| Difficult Run to Ilkley | 3,560.35 mi (5,729.83 km) |
| Difficult Run to Immingham | 3,629.25 mi (5,840.71 km) |
| Difficult Run to Ince-in-Makerfield | 3,536.94 mi (5,692.15 km) |
| Difficult Run to Inverness | 3,412.15 mi (5,491.32 km) |
| Difficult Run to Inverurie | 3,482.19 mi (5,604.05 km) |
| Difficult Run to Ipswich | 3,717.09 mi (5,982.08 km) |
| Difficult Run to Irlam | 3,545.71 mi (5,706.28 km) |
| Difficult Run to Irthlingborough | 3,640.20 mi (5,858.34 km) |
| Difficult Run to Irvine | 3,422.10 mi (5,507.33 km) |
| Difficult Run to Islington | 3,677.72 mi (5,918.72 km) |
