| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Dorr | 1 | 7,905 | 7,931 | -0.16% | 219 | 36 | Township |
| Leighton | 2 | 7,493 | 7,046 | 1.61% | 215 | 35 | Township |
| Laketown | 3 | 6,292 | 5,953 | 0.56% | 292 | 22 | Township |
| Gun Plain | 4 | 6,174 | 6,157 | 0.08% | 182 | 34 | Township |
| Otsego | 5 | 6,000 | 5,913 | -0.02% | 180 | 33 | Township |
| Allegan | 6 | 5,111 | 5,214 | -0.31% | 1,329 | 4 | City |
| Allegan | 7 | 4,919 | 4,710 | 0.51% | 162 | 30 | Township |
| Wayland | 8 | 4,558 | 4,429 | 0.6% | 1,539 | 3 | City |
| Heath | 9 | 4,046 | 3,951 | 0.72% | 114 | 35 | Township |
| Otsego | 10 | 4,028 | 4,114 | -0.42% | 1,983 | 2 | City |
| Lee | 11 | 3,843 | 3,803 | 0.18% | 109 | 35 | Township |
| Saugatuck | 12 | 3,725 | 3,471 | 1% | 161 | 23 | Township |
| Plainwell | 13 | 3,709 | 3,789 | -0.35% | 1,787 | 2 | City |
| Wayland | 14 | 3,623 | 3,575 | 0.08% | 111 | 33 | Township |
| Manlius | 15 | 3,472 | 3,325 | 1.14% | 99 | 35 | Township |
| Overisel | 16 | 3,163 | 3,141 | -0.19% | 89 | 36 | Township |
| Fillmore | 17 | 3,038 | 2,765 | 3.54% | 107 | 28 | Township |
| Hopkins | 18 | 2,751 | 2,751 | -0.11% | 77 | 36 | Township |
| Martin | 19 | 2,723 | 2,728 | 0.07% | 77 | 36 | Township |
| Ganges | 20 | 2,702 | 2,578 | 0.97% | 84 | 32 | Township |
| Trowbridge | 21 | 2,568 | 2,533 | 0.27% | 74 | 35 | Township |
| Monterey | 22 | 2,538 | 2,443 | 0.36% | 71 | 36 | Township |
| Valley | 23 | 2,343 | 2,217 | 0.26% | 71 | 33 | Township |
| Cheshire | 24 | 2,282 | 2,211 | 1.06% | 66 | 35 | Township |
| Watson | 25 | 2,280 | 2,178 | 0.71% | 65 | 35 | Township |
| Clyde | 26 | 2,104 | 2,063 | 0.38% | 60 | 35 | Township |
| Hamilton | 27 | 1,820 | 1,783 | 0.33% | 51 | 36 | Township |
| Fennville | 28 | 1,721 | 1,736 | -0.17% | 1,577 | 1 | City |
| Douglas | 29 | 1,421 | 1,365 | 0.71% | 799 | 2 | City |
| Hamilton | 30 | 1,364 | 1,372 | -0.07% | 40 | 34 | Township |
| Saugatuck | 31 | 884 | 869 | 0.23% | 636 | 1 | City |
| Hopkins | 32 | 636 | 635 | 0% | 1,328 | 0 | Village |
| Hamilton | 33 | 422 | 425 | 0% | 12 | 35 | Township |
| Martin | 34 | 393 | 405 | -0.51% | 513 | 1 | Village |
Dorr is the largest city in Allegan County, with a population of 7,905.
Martin is the smallest city in Allegan County, with a population of 393.
There are 34 cities in Allegan County, Michigan.