1270.0.55.001 - Australian Statistical Geography Standard (ASGS): Volume 1 - Main Structure and Greater Capital City Statistical Areas, July 2011  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 23/12/2010  First Issue
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Contents >> Main Structure >> STATISTICAL AREA LEVEL 1 (SA1)


The SA1s have been designed as the smallest unit for the release of Census data.

SA1s are built from whole Mesh Blocks. Whole SA1s aggregate directly to SA2s in the Main Structure, as well as all of the Non-ABS Structures except LGAs and Tourism Regions. SA1s do not cross S/T borders. There are approximately 55,000 SA1s. In aggregate, they cover the whole of Australia without gaps or overlaps.


The SA1s were delimited using a number of criteria. The design reflects a balance between the respective considerations.

Listed below are the criteria in the approximate order of importance.


SA1s generally have a population of 200 to 800 persons, and an average population of about 400 persons. SA1s in remote and regional areas generally have smaller populations than those in urban areas.

SA1s closely bound small rural towns with a population of 180 persons or more.

Indigenous Population

SA1s are designed to identify discrete indigenous communities with an aim to exclude as much of the non-indigenous population as possible.

SA1s closely bound Indigenous communities with a population of 90 persons or more.

Urban and Rural

SA1s are designed to be either urban or rural in character.

Urban SA1s contain one or more of the following:

  • residential development with a density over 200 persons per square kilometre
  • built infrastructure including
      • ports
      • airports
      • industrial, commercial and retail development
      • large sports complexes
      • educational campuses
      • places of worship
      • military camps
      • research stations
  • local parks and playgrounds
  • local sports facilities and ovals
  • vegetation corridors
  • golf courses
  • cemeteries
  • lakes, rivers, riverbanks, creeks and drainage reserves surrounded by development of an urban character.

Rural SA1s contain one or more of the following:
  • residential development with a density less than 200 persons per square kilometre
  • agriculture
  • national parks
  • defence reserves
  • Indigenous lands
  • mines
  • stockyards
  • lakes, rivers, riverbanks, creeks and drainage reserves not surrounded by development of an urban character.


For the 2011 Edition of the ASGS, SA1s closely reflect LGA boundaries.


SA1s are generally internally connected by road transport. Exceptions include islands, which are either combined with the nearest onshore SA1 or grouped to form an SA1.

Gazetted Suburbs and Localities

Where possible, the SA1s have been designed to contain or aggregate to whole gazetted suburbs or rural localities. In urban areas, the gazetted suburbs usually consist of one or more SA1s.

In regional and remote areas, gazetted localities were sometimes too small to represent an SA1 in their own right. Where this occurred, four general criteria were used to cluster smaller localities:
  • a shared road network
  • similar physical geography
  • shared community facilities
  • being contained within the one LGA.


SA1s have been created in anticipation of development likely to occur up to the time of the 2011 Census of Population and Housing (August 2011).


Prisons, remand centres and juvenile detention centres with a population of over 200 persons are generally represented by their own SA1.

Defence Bases

Defence bases with a population of over 200 persons are generally represented by their own SA1.

Zero SA1

Zero SA1s are SA1s with a nil or nominal population. They are created to represent large unpopulated areas that are not easily combined with surrounding populated SA1s.

They may include one or more of:
  • airports
  • ports
  • commercial developments
  • industrial developments
  • large shopping complexes
  • large sporting complexes
  • large educational campuses
  • research stations
  • large cemeteries
  • 18-hole golf courses
  • national parks
  • large urban parks
  • defence reserves
  • restricted Commonwealth land
  • groups of unpopulated islands
  • very large areas of land which are unlikely ever to be populated, for example extreme desert or otherwise inhospitable terrain
  • lakes.

Special Purpose SA1

There are non-spatial SA1s for Migratory, Offshore, Shipping and No Usual Address in each S/T.


SA1s are not named. They are identified either by an 11-digit fully hierarchical code, or by a truncated 7-digit code comprising the S/T, SA2 and SA1 identifiers. The SA1 identifier is a 2-digit code, assigned within an SA2. An SA1 code is only unique within an S/T when it is preceded by the S/T identifier.

11-digit Code

An 11-digit SA1 code is fully hierarchical, and comprises: S/T identifier, SA4 identifier, SA3 identifier, SA2 identifier and a SA1 identifier.


SA1 50302104118


5 03 02 1041 18

7-digit Code

A 7-digit SA1 code is not fully hierarchical and comprises: S/T identifier, SA2 identifier and SA1 identifier.


SA1 5104118


5 1041 18

Future Allocation of SA1 Codes

In the future, it may be necessary to allocate new codes. If an SA1 is abolished, or changes significantly between editions of the ASGS, the SA1 identifier will be retired and the replacement SA1(s) given the next available previously unused SA1 identifier within the SA2.

SA1 Identifier Ranges

Within each SA2, the SA1 identifier is in the data range 01 to 99.

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