23 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Marion | 1 | 12,304 | 11,271 | 1.65% | 353 | 34.89 | Township |
| Leroy | 2 | 3,800 | 3,792 | 0.05% | 111 | 34.13 | Township |
| Leroy | 3 | 3,693 | 3,659 | 0.16% | 103 | 36 | Township |
| Reed City | 4 | 2,543 | 2,487 | 0.43% | 1,210 | 2.10 | City |
| Hersey | 5 | 1,988 | 1,945 | 0.2% | 56 | 35.35 | Township |
| Evart | 6 | 1,778 | 1,745 | 0.4% | 722 | 2.46 | City |
| Marion | 7 | 1,650 | 1,656 | -0.24% | 65 | 25.57 | Township |
| Marion | 8 | 1,595 | 1,564 | 0.19% | 43 | 36.97 | Township |
| Marion | 9 | 1,552 | 1,568 | -0.32% | 43 | 36.08 | Township |
| Rose Lake | 10 | 1,464 | 1,407 | 0.55% | 44 | 33.61 | Township |
| Burdell | 11 | 1,441 | 1,413 | 0.14% | 39 | 37.27 | Township |
| Evart | 12 | 1,372 | 1,341 | 0.22% | 42 | 32.68 | Township |
| Le Roy | 13 | 1,290 | 1,251 | 0.39% | 37 | 34.99 | Township |
| Sherman | 14 | 1,005 | 990 | -0.1% | 27 | 37.03 | Township |
| Sylvan | 15 | 992 | 968 | 0.3% | 29 | 34.56 | Township |
| Osceola | 16 | 974 | 951 | 0.31% | 29 | 34.05 | Township |
| Marion | 17 | 801 | 783 | 0.5% | 622 | 1.29 | Village |
| Middle Branch | 18 | 801 | 774 | 0.5% | 23 | 35.50 | Township |
| Marion | 19 | 767 | 761 | 0.13% | 31 | 24.38 | Township |
| Orient | 20 | 743 | 728 | 0.13% | 21 | 34.80 | Township |
| Hartwick | 21 | 605 | 591 | 0.33% | 17 | 35.01 | Township |
| Hersey | 22 | 367 | 357 | 0.55% | 334 | 1.10 | Village |
| Tustin | 23 | 259 | 253 | 0.39% | 668 | 0.39 | Village |
Marion is the largest city in Osceola County, with a population of 12,304.
Tustin is the smallest city in Osceola County, with a population of 259.
There are 23 cities in Osceola County, Michigan.