14 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Marshalltown | 1 | 27,577 | 27,569 | 0.01% | 1,436 | 19 | City |
| State Center | 2 | 1,388 | 1,397 | -0.14% | 1,391 | 1 | City |
| Le Grand | 3 | 884 | 909 | -0.56% | 851 | 1 | City |
| Melbourne | 4 | 754 | 788 | -0.92% | 1,428 | 1 | City |
| Gilman | 5 | 524 | 544 | -0.76% | 978 | 1 | City |
| Albion | 6 | 435 | 449 | -0.68% | 721 | 1 | City |
| Liscomb | 7 | 290 | 292 | 0% | 287 | 1 | City |
| Rhodes | 8 | 269 | 271 | 0% | 265 | 1 | City |
| Laurel | 9 | 219 | 219 | 0% | 890 | 0 | City |
| Green Mountain | 10 | 206 | 182 | 2.49% | 300 | 1 | CDP |
| Haverhill | 11 | 161 | 166 | -0.62% | 1,158 | 0 | City |
| Clemons | 12 | 131 | 136 | -0.76% | 524 | 0 | City |
| Ferguson | 13 | 98 | 98 | 0% | 383 | 0 | City |
| St. Anthony | 14 | 76 | 76 | 0% | 124 | 1 | City |
Marshalltown is the largest city in Marshall County, with a population of 27,577.
St. Anthony is the smallest city in Marshall County, with a population of 76.
There are 14 cities in Marshall County, Iowa.