23 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Marion | 1 | 11,906 | 11,272 | 0% | 341 | 35 | Township |
| Leroy | 2 | 3,965 | 3,792 | 1.02% | 116 | 34 | Township |
| Leroy | 3 | 3,694 | 3,658 | 0.14% | 103 | 36 | Township |
| Reed City | 4 | 2,555 | 2,483 | 0.47% | 1,216 | 2 | City |
| Hersey | 5 | 2,031 | 1,944 | 0.89% | 57 | 35 | Township |
| Evart | 6 | 1,798 | 1,749 | 0.45% | 730 | 2 | City |
| Marion | 7 | 1,657 | 1,657 | 0.06% | 65 | 26 | Township |
| Marion | 8 | 1,627 | 1,561 | 0.87% | 44 | 37 | Township |
| Marion | 9 | 1,555 | 1,571 | -0.26% | 43 | 36 | Township |
| Rose Lake | 10 | 1,485 | 1,407 | 0.95% | 44 | 34 | Township |
| Burdell | 11 | 1,463 | 1,409 | 0.76% | 39 | 37 | Township |
| Evart | 12 | 1,398 | 1,341 | 0.79% | 43 | 33 | Township |
| Le Roy | 13 | 1,309 | 1,249 | 0.93% | 37 | 35 | Township |
| Sherman | 14 | 1,028 | 990 | 0.69% | 28 | 37 | Township |
| Sylvan | 15 | 1,020 | 975 | 0.89% | 30 | 35 | Township |
| Osceola | 16 | 994 | 950 | 0.91% | 29 | 34 | Township |
| Middle Branch | 17 | 808 | 775 | 0.75% | 23 | 35 | Township |
| Marion | 18 | 806 | 781 | 0.5% | 626 | 1 | Village |
| Marion | 19 | 778 | 761 | 0.65% | 32 | 24 | Township |
| Orient | 20 | 761 | 728 | 0.93% | 22 | 35 | Township |
| Hartwick | 21 | 612 | 590 | 0.66% | 17 | 35 | Township |
| Hersey | 22 | 369 | 357 | 0.54% | 335 | 1 | Village |
| Tustin | 23 | 256 | 252 | 0.39% | 660 | 0 | Village |
Marion is the largest city in Osceola County, with a population of 11,906.
Tustin is the smallest city in Osceola County, with a population of 256.
There are 23 cities in Osceola County, Michigan.