| Place | Postal Code |
|---|---|
| Biggs Flat, Mount Barker | 5153 |
| Blakiston, Mount Barker | 5250 |
| Brukunga, Mount Barker | 5252 |
| Bugle Ranges, Mount Barker | 5251 |
| Bull Creek, Mount Barker | 5157 |
| Chapel Hill, Mount Barker | 5153 |
| Dawesley, Mount Barker | 5252 |
| Echunga, Mount Barker | 5153 |
| Flaxley, Mount Barker | 5153 |
| Green Hills Range, Mount Barker | 5153 |
| Hahndorf, Mount Barker | 5245 |
| Harrogate, Mount Barker | 5244 |
| Hay Valley, Mount Barker | 5252 |
| Jupiter Creek, Mount Barker | 5153 |
| Kanmantoo, Mount Barker | 5252 |
| Littlehampton, Mount Barker | 5250 |
| Macclesfield, Mount Barker | 5153 |
| Meadows, Mount Barker | 5201 |
| Mount Barker, Mount Barker | 5251 |
| Mount Barker Junction, Mount Barker | 5251 |
| Mount Barker Springs, Mount Barker | 5251 |
| Mount Barker Summit, Mount Barker | 5251 |
| Nairne, Mount Barker | 5252 |
| Paechtown, Mount Barker | 5245 |
| Petwood, Mount Barker | 5254 |
| Prospect Hill, Mount Barker | 5201 |