7 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Newcastle | 1 | 15,888 | 11,170 | 6.32% | 265 | 60.06 | City |
| Blanchard | 2 | 10,148 | 8,935 | 2.45% | 333 | 30.44 | City |
| Purcell | 3 | 7,008 | 6,648 | 1.04% | 460 | 15.25 | City |
| Dibble | 4 | 1,014 | 899 | 2.32% | 136 | 7.47 | Town |
| Washington | 5 | 748 | 673 | 2.05% | 516 | 1.45 | Town |
| Wayne | 6 | 687 | 624 | 1.93% | 1,808 | 0.38 | Town |
| Byars | 7 | 206 | 186 | 1.98% | 134 | 1.53 | Town |
Newcastle is the largest city in McClain County, with a population of 15,888.
Byars is the smallest city in McClain County.
There are 7 cities in McClain County, Oklahoma.