6 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Clarksville | 1 | 9,758 | 9,363 | 0.82% | 536 | 18.22 | City |
| Lamar | 2 | 1,781 | 1,716 | 0.74% | 386 | 4.62 | City |
| Coal Hill | 3 | 810 | 812 | 0% | 289 | 2.80 | City |
| Knoxville | 4 | 667 | 654 | 0.45% | 209 | 3.18 | Town |
| Hartman | 5 | 516 | 515 | 0% | 327 | 1.58 | City |
| Hagarville | 6 | 73 | 24 | -3.95% | 18 | 4.14 | CDP |
Clarksville is the largest city in Johnson County, with a population of 9,758.
Hagarville is the smallest city in Johnson County.
There are 6 cities in Johnson County, Arkansas.