| City | Administrative Division | Country | |
| Island Park | New York | United States | |
| Islandia | New York | United States | |
| Isle of Islay | Scotland | United Kingdom | |
| Isle of Palms | South Carolina | United States | |
| Isles of Scilly | England | United Kingdom | |
| Isleworth | England | United Kingdom | |
| Islip | New York | United States | |
| Isola | Alpes-Maritimes | France | |
| Issaquah | Washington | United States | |
| Issy-les-Moulineaux | Île-de-France | France | |
| Istanbul | Istanbul | Turkey | |
| Itasca | Illinois | United States | |
| Ithaafushi Island | South Male Atoll | Maldives | |
| Ithaca | New York | United States | |
| Itterswiller | Alsace | France | |
| Itu | São Paulo | Brazil | |
| Ivins | Utah | United States | |
| Ivoryton | Connecticut | United States | |
| Ixtapa | Guerrero | Mexico | |
