8 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Laverne | 1 | 1,192 | 1,227 | -0.5% | 1,568 | 1 | Town |
| Laverne | 2 | 1,192 | 1,219 | -0.5% | 1,568 | 1 | Town |
| Buffalo | 3 | 1,015 | 1,039 | -0.39% | 912 | 1 | Town |
| Buffalo | 4 | 1,015 | 1,034 | -0.39% | 912 | 1 | Town |
| Rosston | 5 | 48 | 50 | -2.04% | 175 | 0 | Town |
| Rosston | 6 | 48 | 50 | -2.04% | 175 | 0 | Town |
| May | 7 | 30 | 30 | 0% | 175 | 0 | Town |
| May | 8 | 30 | 30 | 0% | 175 | 0 | Town |
Laverne is the largest city in Harper County, with a population of 1,192.
May is the smallest city in Harper County, with a population of 30.
There are 8 cities in Harper County, Oklahoma.