14 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Marshalltown | 1 | 27,963 | 27,578 | 0.28% | 1,457 | 19 | City |
| State Center | 2 | 1,404 | 1,396 | 0.07% | 1,407 | 1 | City |
| Le Grand | 3 | 888 | 900 | -0.34% | 855 | 1 | City |
| Melbourne | 4 | 766 | 788 | -0.65% | 1,451 | 1 | City |
| Gilman | 5 | 527 | 541 | -0.57% | 983 | 1 | City |
| Albion | 6 | 442 | 450 | -0.45% | 733 | 1 | City |
| Liscomb | 7 | 292 | 289 | 0% | 289 | 1 | City |
| Rhodes | 8 | 269 | 268 | 0% | 265 | 1 | City |
| Laurel | 9 | 214 | 213 | 0% | 870 | 0 | City |
| Green Mountain | 10 | 206 | 182 | 2.49% | 300 | 1 | CDP |
| Haverhill | 11 | 163 | 166 | -0.61% | 1,173 | 0 | City |
| Clemons | 12 | 134 | 137 | -0.74% | 536 | 0 | City |
| Ferguson | 13 | 98 | 97 | 0% | 383 | 0 | City |
| St. Anthony | 14 | 77 | 76 | 0% | 126 | 1 | City |
Marshalltown is the largest city in Marshall County, with a population of 27,963.
St. Anthony is the smallest city in Marshall County, with a population of 77.
There are 14 cities in Marshall County, Iowa.