| Locality | Post Code |
|---|---|
| Leonard, Cass | 58052 |
| Mapleton, Cass | 58059 |
| North River, Cass | 58102 |
| Oxbow, Cass | 58047 |
| Page, Cass | 58064 |
| Prairie Rose, Cass | 58104 |
| Prosper, Cass | 58042 |
| Reiles Acres, Cass | 58102 |
| Riverside, Cass | 58078 |
| Tower City, Cass | 58071 |
| Warren, Cass | 58021 |
| West Fargo, Cass | 58078 |
| Wheatland, Cass | 58079 |
| Wild Rice, Cass | 58047 |