22 cities
| City | County | 2026 Pop. ↓ |
|---|---|---|
| Irvine | Orange County | 323,799 |
| Inglewood | Los Angeles County | 100,462 |
| Indio | Riverside County | 96,674 |
| Imperial Beach | San Diego County | 25,301 |
| Imperial | Imperial County | 22,918 |
| Isla Vista | Santa Barbara County | 11,553 |
| Ione | Amador County | 9,653 |
| Interlaken | Monterey County | 8,392 |
| Indian Wells | Riverside County | 5,093 |
| Ivanhoe | Tulare County | 4,374 |
| Idyllwild-Pine Cove | Riverside County | 3,736 |
| Irwindale | Los Angeles County | 1,455 |
| Inverness | Marin County | 1,417 |
| Inyokern | Kern County | 925 |
| Independence | Inyo County | 923 |
| Indio Hills | Riverside County | 811 |
| Isleton | Sacramento County | 774 |
| Iron Horse | Plumas County | 639 |
| Indianola | Humboldt County | 509 |
| Industry | Los Angeles County | 252 |
| Igo | Shasta County | 134 |
| Idlewild | Tulare County | 70 |