| Localité | Code postal |
|---|---|
| Belding, Ionia | 48809 |
| Clarksville, Ionia | 48815 |
| Fenwick, Ionia | 48834 |
| Freeport, Ionia | 49325 |
| Hubbardston, Ionia | 48845 |
| Ionia, Ionia | 48846 |
| Lake Odessa, Ionia | 48849 |
| Lowell, Ionia | 49331 |
| Lyons, Ionia | 48851 |
| Muir, Ionia | 48860 |
| Orleans, Ionia | 48865 |
| Palo, Ionia | 48870 |
| Pewamo, Ionia | 48873 |
| Portland, Ionia | 48875 |
| Saranac, Ionia | 48881 |
| Smyrna, Ionia | 48887 |
| Sunfield, Ionia | 48890 |
| Westphalia, Ionia | 48894 |