13 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Marshalltown | 1 | 28,040 | 27,578 | 0.28% | 1,461 | 19 | City |
| State Center | 2 | 1,406 | 1,396 | 0.14% | 1,409 | 1 | City |
| Le Grand | 3 | 886 | 900 | -0.23% | 853 | 1 | City |
| Melbourne | 4 | 762 | 788 | -0.52% | 1,443 | 1 | City |
| Gilman | 5 | 524 | 541 | -0.57% | 978 | 1 | City |
| Albion | 6 | 441 | 450 | -0.23% | 731 | 1 | City |
| Liscomb | 7 | 293 | 289 | 0.34% | 290 | 1 | City |
| Rhodes | 8 | 269 | 268 | 0% | 265 | 1 | City |
| Laurel | 9 | 214 | 213 | 0% | 870 | 0 | City |
| Haverhill | 10 | 163 | 166 | 0% | 1,173 | 0 | City |
| Clemons | 11 | 134 | 137 | 0% | 536 | 0 | City |
| Ferguson | 12 | 98 | 97 | 0% | 383 | 0 | City |
| St. Anthony | 13 | 77 | 76 | 0% | 126 | 1 | City |
Marshalltown is the largest city in Marshall County, with a population of 28,040.
St. Anthony is the smallest city in Marshall County, with a population of 77.
There are 13 cities in Marshall County, Iowa.