11 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Clayton | 1 | 32,564 | 26,693 | 3.74% | 1,945 | 16.74 | Town |
| Smithfield | 2 | 13,191 | 11,383 | 2.82% | 1,038 | 12.70 | Town |
| Selma | 3 | 7,446 | 6,360 | 3% | 1,377 | 5.41 | Town |
| Archer Lodge | 4 | 5,719 | 4,834 | 3.19% | 631 | 9.07 | Town |
| Benson | 5 | 4,666 | 4,003 | 2.93% | 1,561 | 2.99 | Town |
| Wilson's Mills | 6 | 2,998 | 2,553 | 3.06% | 470 | 6.38 | Town |
| Four Oaks | 7 | 2,705 | 2,267 | 3.36% | 963 | 2.81 | Town |
| Pine Level | 8 | 2,419 | 2,064 | 3.02% | 1,354 | 1.79 | Town |
| Kenly | 9 | 1,733 | 1,505 | 2.73% | 922 | 1.88 | Town |
| Princeton | 10 | 1,553 | 1,323 | 3.05% | 1,333 | 1.17 | Town |
| Micro | 11 | 540 | 459 | 3.05% | 1,289 | 0.42 | Town |
Clayton is the largest city in Johnston County, with a population of 32,564.
Micro is the smallest city in Johnston County.
There are 11 cities in Johnston County, North Carolina.