This table ranks all 20 ZIP codes in the Marshalltown, IA MSA by estimated 2022 population, from highest to lowest.
| # | ZIP Code | Place Name | Population (2022) |
|---|---|---|---|
| 1 | ZIP 50158 | Marshalltown | 31,047 |
| 2 | ZIP 50247 | State Center | 2,411 |
| 3 | ZIP 50621 | Conrad | 1,641 |
| 4 | ZIP 50635 | Gladbrook | 1,344 |
| 5 | ZIP 50162 | Melbourne | 1,302 |
| 6 | ZIP 50632 | Garwin | 1,296 |
| 7 | ZIP 50055 | Collins | 1,260 |
| 8 | ZIP 50106 | Gilman | 1,182 |
| 9 | ZIP 50005 | Albion | 859 |
| 10 | ZIP 50258 | Union | 831 |
| 11 | ZIP 50142 | Le Grand | 790 |
| 12 | ZIP 50120 | Haverhill | 537 |
| 13 | ZIP 50206 | New Providence | 500 |
| 14 | ZIP 50141 | Laurel | 499 |
| 15 | ZIP 50234 | Rhodes | 482 |
| 16 | ZIP 50609 | Beaman | 381 |
| 17 | ZIP 50148 | Liscomb | 376 |
| 18 | ZIP 50051 | Clemons | 277 |
| 19 | ZIP 50239 | Saint Anthony | 139 |
| 20 | ZIP 50078 | Ferguson | 102 |