22 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Tishomingo | 1 | 3,079 | 3,107 | -0.13% | 584 | 5 | City |
| Tishomingo | 2 | 3,079 | 3,098 | -0.13% | 584 | 5 | City |
| Mannsville | 3 | 738 | 728 | 0.27% | 243 | 3 | Town |
| Mannsville | 4 | 738 | 725 | 0.27% | 243 | 3 | Town |
| Ravia | 5 | 467 | 466 | 0% | 824 | 1 | Town |
| Ravia | 6 | 467 | 464 | 0% | 824 | 1 | Town |
| Wapanucka | 7 | 391 | 387 | 0.26% | 602 | 1 | Town |
| Wapanucka | 8 | 391 | 386 | 0.26% | 602 | 1 | Town |
| Coleman | 9 | 371 | 327 | 7.23% | 97 | 4 | CDP |
| Mill Creek | 10 | 291 | 291 | 0% | 758 | 0 | Town |
| Mill Creek | 11 | 291 | 290 | 0% | 758 | 0 | Town |
| Milburn | 12 | 250 | 250 | 0% | 533 | 0 | Town |
| Milburn | 13 | 250 | 249 | 0% | 533 | 0 | Town |
| Kenefic | 14 | 161 | 147 | 1.26% | 162 | 1 | Town |
| Kenefic | 15 | 161 | 148 | 1.26% | 162 | 1 | Town |
| Connerville | 16 | 156 | 147 | 6.85% | 78 | 2 | CDP |
| Bromide | 17 | 121 | 120 | 0% | 180 | 1 | Town |
| Bromide | 18 | 121 | 120 | 0% | 180 | 1 | Town |
| Pontotoc | 19 | 104 | 31 | 7.22% | 97 | 1 | CDP |
| Earl | 20 | 99 | 111 | 7.61% | 329 | 0 | CDP |
| Emet | 21 | 64 | 50 | 6.67% | 147 | 0 | CDP |
| Reagan | 22 | 50 | 47 | 6.38% | 56 | 1 | CDP |
Tishomingo is the largest city in Johnston County, with a population of 3,079.
Reagan is the smallest city in Johnston County, with a population of 50.
There are 22 cities in Johnston County, Oklahoma.