28 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Attica | 1 | 8,762 | 7,381 | 3.82% | 319 | 27 | Township |
| Attica | 2 | 8,762 | 7,433 | 3.82% | 319 | 27 | Township |
| Anthony | 3 | 2,043 | 2,095 | -0.44% | 634 | 3 | City |
| Anthony | 4 | 2,043 | 2,088 | -0.44% | 634 | 3 | City |
| Harper | 5 | 1,291 | 1,306 | -0.15% | 795 | 2 | City |
| Harper | 6 | 1,291 | 1,301 | -0.15% | 795 | 2 | City |
| Township 1 | 7 | 835 | 841 | 0.36% | 5 | 181 | Township |
| Township 1 | 8 | 835 | 839 | 0.36% | 5 | 181 | Township |
| Attica | 9 | 504 | 515 | -0.4% | 795 | 1 | City |
| Attica | 10 | 504 | 514 | -0.4% | 795 | 1 | City |
| Township 5 | 11 | 411 | 413 | 0.24% | 4 | 106 | Township |
| Township 5 | 12 | 411 | 412 | 0.24% | 4 | 106 | Township |
| Township 3 | 13 | 289 | 286 | 1.05% | 2 | 146 | Township |
| Township 3 | 14 | 289 | 285 | 1.05% | 2 | 146 | Township |
| Township 6 | 15 | 268 | 270 | 0.37% | 2 | 108 | Township |
| Township 6 | 16 | 268 | 269 | 0.37% | 2 | 108 | Township |
| Township 4 | 17 | 189 | 192 | 0% | 2 | 115 | Township |
| Township 4 | 18 | 189 | 191 | 0% | 2 | 115 | Township |
| Harper | 19 | 135 | 133 | 0% | 4 | 36 | Township |
| Harper | 20 | 135 | 133 | 0% | 4 | 36 | Township |
| Township 2 | 21 | 86 | 82 | 2.38% | 1 | 140 | Township |
| Township 2 | 22 | 86 | 82 | 2.38% | 1 | 140 | Township |
| Bluff City | 23 | 43 | 45 | -2.27% | 85 | 1 | City |
| Bluff City | 24 | 43 | 45 | -2.27% | 85 | 1 | City |
| Danville | 25 | 29 | 29 | 0% | 349 | 0 | City |
| Danville | 26 | 29 | 29 | 0% | 349 | 0 | City |
| Waldron | 27 | 9 | 9 | 0% | 29 | 0 | City |
| Waldron | 28 | 9 | 9 | 0% | 29 | 0 | City |
Attica is the largest city in Harper County, with a population of 8,762.
Waldron is the smallest city in Harper County, with a population of 9.
There are 28 cities in Harper County, Kansas.