26 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Osborne | 1 | 1,289 | 1,324 | -0.54% | 838 | 1.54 | City |
| Ross township | 2 | 850 | 887 | -1.28% | 24 | 35.49 | Township |
| Downs | 3 | 780 | 804 | -0.64% | 696 | 1.12 | City |
| Natoma township | 4 | 305 | 325 | -1.93% | 8 | 35.92 | Township |
| Natoma | 5 | 290 | 304 | -1.02% | 687 | 0.42 | City |
| Osborne township | 6 | 216 | 220 | -0.46% | 6 | 34.44 | Township |
| Sumner township | 7 | 145 | 153 | -1.36% | 3 | 53.64 | Township |
| Downs township | 8 | 139 | 141 | -0.71% | 4 | 35.11 | Township |
| Bethany township | 9 | 138 | 150 | -2.82% | 4 | 36.06 | Township |
| Penn township | 10 | 128 | 134 | -1.54% | 3 | 46.07 | Township |
| Alton | 11 | 95 | 100 | -1.04% | 307 | 0.31 | City |
| Portis | 12 | 82 | 87 | -1.2% | 314 | 0.26 | City |
| Tilden township | 13 | 70 | 73 | -1.41% | 2 | 41.10 | Township |
| Bloom township | 14 | 63 | 66 | -1.56% | 1 | 53.91 | Township |
| Corinth township | 15 | 38 | 41 | -2.56% | 1 | 35.45 | Township |
| Valley township | 16 | 33 | 36 | -2.94% | 1 | 36.09 | Township |
| Delhi township | 17 | 28 | 31 | -3.45% | 1 | 53.59 | Township |
| Jackson township | 18 | 27 | 30 | -3.57% | 1 | 35.92 | Township |
| Hawkeye township | 19 | 25 | 28 | -3.85% | 1 | 35.58 | Township |
| Round Mound township | 20 | 25 | 28 | -3.85% | 1 | 35.68 | Township |
| Grant township | 21 | 22 | 22 | 0% | 1 | 35.42 | Township |
| Mount Ayr township | 22 | 21 | 21 | 0% | 1 | 35.72 | Township |
| Victor township | 23 | 19 | 19 | 0% | 1 | 35.86 | Township |
| Hancock township | 24 | 18 | 18 | 0% | 1 | 35.94 | Township |
| Kill Creek township | 25 | 9 | 9 | 0% | 0.00 | 35.98 | Township |
| Covert township | 26 | 8 | 8 | 0% | 0.00 | 35.85 | Township |
Osborne is the largest city in Osborne County, with a population of 1,289.
Covert township is the smallest city in Osborne County.
There are 26 cities in Osborne County, Kansas.