15 cities
| City | County | 2025 Pop. ↓ |
|---|---|---|
| Jurupa Valley | Riverside County | 108,853 |
| Joshua Tree | San Bernardino County | 6,585 |
| Jamul | San Diego County | 5,982 |
| Jackson | Amador County | 5,100 |
| Jamestown | Tuolumne County | 3,819 |
| Janesville | Lassen County | 2,949 |
| Julian | San Diego County | 1,346 |
| Junction City | Trinity County | 1,324 |
| Jones Valley | Shasta County | 1,211 |
| Johnstonville | Lassen County | 1,106 |
| Johnson Park | Shasta County | 951 |
| Jacumba | San Diego County | 931 |
| June Lake | Mono County | 220 |
| Johannesburg | Kern County | 74 |
| Jovista | Kern County | 54 |