| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Alma | 1 | 9,285 | 9,440 | -0.2% | 1,576 | 6 | City |
| St. Louis | 2 | 7,409 | 7,450 | 0.04% | 2,235 | 3 | City |
| Ithaca | 3 | 2,798 | 2,850 | -0.32% | 489 | 6 | City |
| Wheeler | 4 | 2,561 | 2,607 | -0.31% | 71 | 36 | Township |
| Pine River | 5 | 2,356 | 2,357 | -0.04% | 78 | 30 | Township |
| Seville | 6 | 2,100 | 2,127 | -0.19% | 59 | 36 | Township |
| Sumner | 7 | 1,849 | 1,861 | -0.05% | 52 | 36 | Township |
| Arcada | 8 | 1,636 | 1,663 | -0.24% | 51 | 32 | Township |
| Bethany | 9 | 1,288 | 1,307 | -0.23% | 37 | 35 | Township |
| Elba | 10 | 1,272 | 1,288 | -0.24% | 36 | 35 | Township |
| Breckenridge | 11 | 1,261 | 1,286 | -0.32% | 1,023 | 1 | Village |
| Newark | 12 | 1,110 | 1,122 | -0.27% | 32 | 34 | Township |
| North Star | 13 | 873 | 895 | -0.57% | 26 | 34 | Township |
| Emerson | 14 | 833 | 848 | -0.24% | 24 | 34 | Township |
| North Shade | 15 | 549 | 560 | -0.36% | 15 | 36 | Township |
| Ashley | 16 | 512 | 515 | -0.19% | 764 | 1 | Village |
| Lafayette | 17 | 504 | 517 | -0.4% | 14 | 36 | Township |
| Perrinton | 18 | 387 | 391 | -0.26% | 612 | 1 | Village |
Alma is the largest city in Gratiot County, with a population of 9,285.
Perrinton is the smallest city in Gratiot County, with a population of 387.
There are 18 cities in Gratiot County, Michigan.