This table ranks all 16 ZIP codes in the Spencer, IA MSA by estimated 2022 population, from highest to lowest.
| # | ZIP Code | Place Name | Population (2022) |
|---|---|---|---|
| 1 | ZIP 51301 | Spencer | 12,326 |
| 2 | ZIP 51346 | Hartley | 2,201 |
| 3 | ZIP 51358 | Ruthven | 1,259 |
| 4 | ZIP 50585 | Sioux Rapids | 1,207 |
| 5 | ZIP 51058 | Sutherland | 982 |
| 6 | ZIP 51338 | Everly | 933 |
| 7 | ZIP 51357 | Royal | 744 |
| 8 | ZIP 51364 | Terril | 708 |
| 9 | ZIP 51047 | Peterson | 690 |
| 10 | ZIP 51033 | Linn Grove | 460 |
| 11 | ZIP 51333 | Dickens | 394 |
| 12 | ZIP 51366 | Webb | 303 |
| 13 | ZIP 51343 | Greenville | 284 |
| 14 | ZIP 50515 | Ayrshire | 271 |
| 15 | ZIP 51340 | Fostoria | 93 |
| 16 | ZIP 51341 | Gillett Grove | 39 |