| Locality | Post Code |
|---|---|
| Dunlap, Harrison | 51529 |
| Little Sioux, Harrison | 51545 |
| Logan, Harrison | 51546 |
| Magnolia, Harrison | 51550 |
| Missouri Valley, Harrison | 51555 |
| Modale, Harrison | 51556 |
| Mondamin, Harrison | 51557 |
| Moorhead, Harrison | 51558 |
| Neola, Harrison | 51559 |
| Persia, Harrison | 51563 |
| Pisgah, Harrison | 51564 |
| Portsmouth, Harrison | 51565 |
| Shelby, Harrison | 51570 |
| Woodbine, Harrison | 51579 |