1780 is also the box code for 8 post office box locations.
PO Box locations with code 1780
| Suburb | Town | Province |
|---|---|---|
| Jachfontein | Westonaria | Gauteng |
| Kloofmyn | Westonaria | Gauteng |
| Leeudoring Ext | Westonaria | Gauteng |
| Simunye Ext 1 | Westonaria | Gauteng |
| Simunye Ext 4 | Westonaria | Gauteng |
| Wagterskop | Westonaria | Gauteng |
| Wagterskop Ext | Westonaria | Gauteng |
| Westonaria | Westonaria | Gauteng |