34 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Dorr | 1 | 7,930 | 7,932 | -0.04% | 219 | 36 | Township |
| Leighton | 2 | 7,360 | 7,041 | 1.45% | 211 | 35 | Township |
| Laketown | 3 | 6,249 | 5,957 | 0.42% | 290 | 22 | Township |
| Gun Plain | 4 | 6,149 | 6,159 | -0.19% | 181 | 34 | Township |
| Otsego | 5 | 5,984 | 5,912 | 0.03% | 180 | 33 | Township |
| Allegan | 6 | 5,136 | 5,216 | -0.31% | 1,335 | 4 | City |
| Allegan | 7 | 4,901 | 4,706 | 0.93% | 161 | 30 | Township |
| Wayland | 8 | 4,570 | 4,435 | 0.59% | 1,543 | 3 | City |
| Otsego | 9 | 4,017 | 4,110 | -0.47% | 1,978 | 2 | City |
| Heath | 10 | 3,979 | 3,944 | 0.23% | 112 | 35 | Township |
| Lee | 11 | 3,830 | 3,806 | 0.13% | 109 | 35 | Township |
| Plainwell | 12 | 3,722 | 3,790 | -0.37% | 1,794 | 2 | City |
| Saugatuck | 13 | 3,681 | 3,466 | 1.15% | 159 | 23 | Township |
| Wayland | 14 | 3,606 | 3,576 | 0.03% | 110 | 33 | Township |
| Manlius | 15 | 3,398 | 3,319 | 0.32% | 97 | 35 | Township |
| Overisel | 16 | 3,167 | 3,136 | -0.03% | 89 | 36 | Township |
| Fillmore | 17 | 2,887 | 2,760 | 2.23% | 102 | 28 | Township |
| Hopkins | 18 | 2,769 | 2,753 | 0.54% | 78 | 36 | Township |
| Martin | 19 | 2,718 | 2,730 | -0.18% | 76 | 36 | Township |
| Ganges | 20 | 2,661 | 2,574 | 0.64% | 83 | 32 | Township |
| Trowbridge | 21 | 2,546 | 2,532 | 0.12% | 73 | 35 | Township |
| Monterey | 22 | 2,519 | 2,441 | 0.2% | 71 | 36 | Township |
| Valley | 23 | 2,363 | 2,221 | 1.07% | 72 | 33 | Township |
| Watson | 24 | 2,247 | 2,178 | 0.13% | 64 | 35 | Township |
| Cheshire | 25 | 2,245 | 2,213 | 0.4% | 64 | 35 | Township |
| Clyde | 26 | 2,093 | 2,062 | 0.34% | 60 | 35 | Township |
| Hamilton | 27 | 1,807 | 1,783 | 0% | 50 | 36 | Township |
| Fennville | 28 | 1,730 | 1,742 | -0.17% | 1,586 | 1 | City |
| Douglas | 29 | 1,422 | 1,370 | 0.71% | 799 | 2 | City |
| Hamilton | 30 | 1,364 | 1,368 | 0% | 40 | 34 | Township |
| Saugatuck | 31 | 881 | 868 | 0.23% | 633 | 1 | City |
| Hopkins | 32 | 636 | 635 | 0% | 1,328 | 0 | Village |
| Hamilton | 33 | 424 | 426 | 0% | 12 | 35 | Township |
| Martin | 34 | 398 | 406 | -0.5% | 520 | 1 | Village |
Dorr is the largest city in Allegan County, with a population of 7,930.
Martin is the smallest city in Allegan County, with a population of 398.
There are 34 cities in Allegan County, Michigan.