10 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Munising township | 1 | 2,796 | 2,877 | -0.14% | 14 | 202.25 | Township |
| Munising | 2 | 1,957 | 1,972 | -0.15% | 372 | 5.26 | City |
| Rock River township | 3 | 1,237 | 1,242 | -0.16% | 15 | 80.69 | Township |
| Au Train township | 4 | 1,020 | 1,023 | -0.1% | 7 | 141.28 | Township |
| Mathias township | 5 | 526 | 531 | -0.38% | 7 | 70.68 | Township |
| Limestone township | 6 | 387 | 389 | -0.26% | 5 | 74.19 | Township |
| Onota township | 7 | 371 | 370 | 0% | 4 | 87.73 | Township |
| Grand Marais | 8 | 320 | 317 | 7.02% | 169 | 1.89 | CDP |
| Chatham | 9 | 215 | 217 | 0% | 88 | 2.45 | Village |
| Grand Island township | 10 | 32 | 32 | 0% | 1 | 22.48 | Township |
Munising township is the largest city in Alger County, with a population of 2,796.
Grand Island township is the smallest city in Alger County.
There are 10 cities in Alger County, Michigan.