24 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Osage City | 1 | 2,784 | 2,856 | -0.54% | 884 | 3 | City |
| Ridgeway | 2 | 2,364 | 2,390 | -0.55% | 57 | 42 | Township |
| Elk | 3 | 1,809 | 1,822 | -0.33% | 33 | 54 | Township |
| Burlingame | 4 | 1,701 | 1,719 | -0.64% | 24 | 72 | Township |
| Valley Brook | 5 | 1,514 | 1,504 | 0.07% | 38 | 40 | Township |
| Carbondale | 6 | 1,295 | 1,349 | -0.84% | 1,772 | 1 | City |
| Junction | 7 | 1,227 | 1,198 | -0.08% | 25 | 50 | Township |
| Scranton | 8 | 1,105 | 1,114 | -0.63% | 31 | 36 | Township |
| Lyndon | 9 | 1,037 | 1,037 | 0% | 1,163 | 1 | City |
| Overbrook | 10 | 990 | 1,027 | -0.8% | 1,820 | 1 | City |
| Vassar | 11 | 970 | 865 | 3.08% | 200 | 5 | CDP |
| Burlingame | 12 | 932 | 966 | -0.75% | 1,054 | 1 | City |
| Melvern | 13 | 740 | 741 | -0.4% | 17 | 45 | Township |
| Scranton | 14 | 638 | 652 | -0.47% | 592 | 1 | City |
| Fairfax | 15 | 623 | 613 | -0.16% | 14 | 43 | Township |
| Agency | 16 | 416 | 415 | -0.24% | 13 | 33 | Township |
| Melvern | 17 | 343 | 353 | -0.58% | 963 | 0 | City |
| Grant | 18 | 302 | 300 | -0.98% | 8 | 36 | Township |
| Quenemo | 19 | 286 | 288 | -0.35% | 644 | 0 | City |
| Superior | 20 | 248 | 245 | -0.8% | 7 | 36 | Township |
| Olivet | 21 | 228 | 223 | 0% | 4 | 56 | Township |
| Dragoon | 22 | 206 | 203 | -0.96% | 6 | 36 | Township |
| Barclay | 23 | 154 | 152 | -0.65% | 3 | 48 | Township |
| Arvonia | 24 | 110 | 107 | 0.92% | 3 | 43 | Township |
Osage City is the largest city in Osage County, with a population of 2,784.
Arvonia is the smallest city in Osage County, with a population of 110.
There are 24 cities in Osage County, Kansas.