18 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Alma | 1 | 9,289 | 9,468 | -0.32% | 1,577 | 6 | City |
| St. Louis | 2 | 7,470 | 7,455 | 0.04% | 2,253 | 3 | City |
| Ithaca | 3 | 2,795 | 2,849 | -0.32% | 488 | 6 | City |
| Wheeler | 4 | 2,569 | 2,604 | -0.19% | 72 | 36 | Township |
| Pine River | 5 | 2,359 | 2,361 | 0.04% | 78 | 30 | Township |
| Seville | 6 | 2,116 | 2,125 | 0% | 60 | 36 | Township |
| Sumner | 7 | 1,856 | 1,859 | 0.05% | 52 | 36 | Township |
| Arcada | 8 | 1,642 | 1,669 | -0.18% | 51 | 32 | Township |
| Bethany | 9 | 1,284 | 1,307 | -0.31% | 37 | 35 | Township |
| Elba | 10 | 1,271 | 1,287 | -0.16% | 36 | 35 | Township |
| Breckenridge | 11 | 1,261 | 1,285 | -0.32% | 1,023 | 1 | Village |
| Newark | 12 | 1,110 | 1,112 | 0.09% | 32 | 34 | Township |
| North Star | 13 | 880 | 894 | -0.11% | 26 | 34 | Township |
| Emerson | 14 | 830 | 848 | -0.36% | 24 | 34 | Township |
| North Shade | 15 | 549 | 559 | -0.36% | 15 | 36 | Township |
| Ashley | 16 | 511 | 514 | 0% | 763 | 1 | Village |
| Lafayette | 17 | 506 | 518 | -0.39% | 14 | 36 | Township |
| Perrinton | 18 | 392 | 392 | 0% | 620 | 1 | Village |
Alma is the largest city in Gratiot County, with a population of 9,289.
Perrinton is the smallest city in Gratiot County, with a population of 392.
There are 18 cities in Gratiot County, Michigan.