The various geographical areas, or spatial units, which build the different classification structures are as follows:
- Census Collection District (CD)
- Statistical Local Area (SLA)
- Statistical Subdivision (SSD)
- Statistical Division (SD)
- State and Territory (S/T)
- Statistical District (S Dist.)
- Local Government Area (LGA)
- Statistical Region Sector (SRS)
- Statistical Region (SR)
- Major Statistical Region (MSR)
- Urban Centre/Locality (UC/L)
- Section(s) of State (SOS)
- Remoteness Area (RA).
During Population Census years, the smallest spatial unit is the CD. It is the basic building block of the classification structures. Between censuses, the smallest spatial unit is the SLA. Thus for those years when a census is held, all the above spatial units are defined. In intercensal years, all units except CDs, UC/Ls, SOS and RAs are defined.
These spatial units are individually explained in Chapters 2-8.