| Holyhead to Iselin (New Jersey) | 3,263.07 mi (5,251.41 km) |
| Holyhead to Isla Vista (California) | 5,246.38 mi (8,443.23 km) |
| Holyhead to Issaquah (Washington) | 4,563.71 mi (7,344.59 km) |
| Holyhead to Ithaca (New York) | 3,267.04 mi (5,257.79 km) |
| Holyhead to Ives Estates (Florida) | 4,213.36 mi (6,780.75 km) |
| Holyhead to Jackson (Michigan) | 3,582.95 mi (5,766.20 km) |
| Holyhead to Jackson (Mississippi) | 4,292.23 mi (6,907.68 km) |
| Holyhead to Jackson (Missouri) | 4,016.24 mi (6,463.51 km) |
| Holyhead to Jackson (Tennessee) | 4,070.02 mi (6,550.07 km) |
| Holyhead to Jackson (Wyoming) | 4,453.77 mi (7,167.65 km) |
| Holyhead to Jacksonville (Alabama) | 4,040.55 mi (6,502.63 km) |
| Holyhead to Jacksonville (Arkansas) | 4,236.58 mi (6,818.11 km) |
| Holyhead to Jacksonville (Florida) | 4,050.79 mi (6,519.11 km) |
| Holyhead to Jacksonville (Illinois) | 3,923.44 mi (6,314.17 km) |
| Holyhead to Jacksonville (North Carolina) | 3,659.30 mi (5,889.07 km) |
