28 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Sabetha | 1 | 2,463 | 2,538 | -0.61% | 739 | 3 | City |
| Seneca | 2 | 2,143 | 2,140 | 0.05% | 1,199 | 2 | City |
| Illinois | 3 | 519 | 539 | -0.95% | 15 | 36 | Township |
| Centralia | 4 | 498 | 483 | 0.61% | 1,097 | 0 | City |
| Wetmore | 5 | 446 | 467 | -1.11% | 12 | 36 | Township |
| Rock Creek | 6 | 437 | 457 | -0.91% | 13 | 34 | Township |
| Berwick | 7 | 384 | 398 | -0.78% | 11 | 36 | Township |
| Wetmore | 8 | 336 | 346 | -0.59% | 868 | 0 | City |
| Harrison | 9 | 302 | 307 | -0.33% | 8 | 36 | Township |
| Mitchell | 10 | 299 | 311 | -0.99% | 8 | 36 | Township |
| Corning | 11 | 208 | 215 | -0.48% | 684 | 0 | City |
| Gilman | 12 | 194 | 200 | -0.51% | 5 | 36 | Township |
| Center | 13 | 162 | 170 | -1.22% | 4 | 36 | Township |
| Bern | 14 | 157 | 164 | -0.63% | 553 | 0 | City |
| Adams | 15 | 157 | 165 | -1.26% | 4 | 36 | Township |
| Capioma | 16 | 124 | 129 | -0.8% | 3 | 36 | Township |
| Nemaha | 17 | 124 | 129 | -0.8% | 3 | 35 | Township |
| Baileyville | 18 | 107 | 164 | -4.46% | 88 | 1 | CDP |
| Wheaton | 19 | 107 | 99 | 1.9% | 695 | 0 | City |
| Goff | 20 | 105 | 105 | 0% | 510 | 0 | City |
| Red Vermillion | 21 | 102 | 104 | 0% | 3 | 36 | Township |
| Neuchatel | 22 | 96 | 100 | -1.03% | 3 | 36 | Township |
| Clear Creek | 23 | 95 | 99 | -1.04% | 3 | 36 | Township |
| Reilly | 24 | 91 | 95 | -1.09% | 3 | 36 | Township |
| Granada | 25 | 88 | 92 | -1.12% | 2 | 36 | Township |
| Oneida | 26 | 57 | 59 | 0% | 248 | 0 | City |
| St. Benedict | 27 | 40 | 124 | 8.11% | 28 | 1 | CDP |
| Kelly | 28 | 1 | 3 | 0% | 4 | 0 | CDP |
Sabetha is the largest city in Nemaha County, with a population of 2,463.
Kelly is the smallest city in Nemaha County, with a population of 1.
There are 28 cities in Nemaha County, Kansas.