| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Marshalltown | 1 | 27,564 | 27,580 | 0.1% | 1,436 | 19 | City |
| State Center | 2 | 1,388 | 1,397 | -0.07% | 1,391 | 1 | City |
| Le Grand | 3 | 879 | 900 | -0.45% | 846 | 1 | City |
| Melbourne | 4 | 755 | 788 | -0.66% | 1,430 | 1 | City |
| Gilman | 5 | 523 | 544 | -0.76% | 976 | 1 | City |
| Albion | 6 | 435 | 452 | -0.68% | 721 | 1 | City |
| Liscomb | 7 | 288 | 289 | 0% | 285 | 1 | City |
| Rhodes | 8 | 264 | 268 | -0.38% | 260 | 1 | City |
| Laurel | 9 | 211 | 213 | 0% | 858 | 0 | City |
| Haverhill | 10 | 160 | 166 | -1.23% | 1,151 | 0 | City |
| Clemons | 11 | 131 | 138 | -0.76% | 524 | 0 | City |
| Ferguson | 12 | 97 | 98 | 0% | 379 | 0 | City |
| St. Anthony | 13 | 73 | 73 | 0% | 119 | 1 | City |
Marshalltown is the largest city in Marshall County, with a population of 27,564.
St. Anthony is the smallest city in Marshall County, with a population of 73.
There are 13 cities in Marshall County, Iowa.