25 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Sabetha | 1 | 2,445 | 2,538 | -0.61% | 734 | 3 | City |
| Seneca | 2 | 2,140 | 2,142 | 0% | 1,197 | 2 | City |
| Illinois | 3 | 524 | 538 | -0.19% | 15 | 36 | Township |
| Centralia | 4 | 495 | 482 | 0.41% | 1,090 | 0 | City |
| Wetmore | 5 | 455 | 471 | -0.44% | 13 | 36 | Township |
| Rock Creek | 6 | 439 | 457 | -0.45% | 13 | 34 | Township |
| Berwick | 7 | 384 | 398 | -0.52% | 11 | 36 | Township |
| Wetmore | 8 | 334 | 348 | -0.6% | 863 | 0 | City |
| Mitchell | 9 | 300 | 309 | -0.33% | 8 | 36 | Township |
| Harrison | 10 | 299 | 308 | -0.33% | 8 | 36 | Township |
| Corning | 11 | 206 | 214 | -0.48% | 678 | 0 | City |
| Gilman | 12 | 192 | 202 | -1.03% | 5 | 36 | Township |
| Center | 13 | 162 | 169 | -0.61% | 4 | 36 | Township |
| Bern | 14 | 160 | 166 | -0.62% | 563 | 0 | City |
| Adams | 15 | 151 | 164 | -1.95% | 4 | 36 | Township |
| Capioma | 16 | 126 | 129 | 0% | 4 | 36 | Township |
| Nemaha | 17 | 116 | 128 | -2.52% | 3 | 35 | Township |
| Wheaton | 18 | 110 | 98 | 1.85% | 714 | 0 | City |
| Goff | 19 | 102 | 104 | 0% | 495 | 0 | City |
| Red Vermillion | 20 | 101 | 104 | 0% | 3 | 36 | Township |
| Neuchatel | 21 | 95 | 100 | -1.04% | 3 | 36 | Township |
| Clear Creek | 22 | 94 | 99 | -1.05% | 3 | 36 | Township |
| Granada | 23 | 90 | 92 | 0% | 3 | 36 | Township |
| Reilly | 24 | 89 | 94 | -1.11% | 2 | 36 | Township |
| Oneida | 25 | 57 | 60 | 0% | 248 | 0 | City |
Sabetha is the largest city in Nemaha County, with a population of 2,445.
Oneida is the smallest city in Nemaha County, with a population of 57.
There are 25 cities in Nemaha County, Kansas.