Statistical Area Level 1

Statistical Areas Level 1 (SA1) are geographic areas built from whole Mesh Blocks (MB). Whole SA1s aggregate to form Statistical Areas Level 2 (SA2). SA1s are designed to maximise the geographic detail available for Census of Population and Housing data.

There are 63,485 SA1s covering the whole of Australia without gaps or overlaps. This includes 34 non-spatial special purpose codes representing populations that are difficult to define geographically such as people in transit or have no fixed address. Migratory and No Usual Address are examples of this type of SA1.

SA1s are also used as the building blocks for the Indigenous Structure and the Remoteness Structure.

SA1s are designed using multiple criteria, listed below in approximate order of importance.

SA1s generally have a population of 200 to 800 people, with an average population of about 400. SA1s in remote and regional areas generally have smaller populations than those in urban areas. Some low population count SA1s are permitted to accommodate other design criteria.

Where possible, SA1s are designed to represent Aboriginal and Torres Strait Islander communities, particularly in remote areas.

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

Urban SA1s include one or more of the following:

• residential development with a density greater than 200 people per square kilometre
• built infrastructure including ports, airports with paved runways, industrial, commercial and retail development, large sporting complexes, education campuses, places of worship, military camps and 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
• sewerage facilities, waste disposal facilities, hospitals, transport hubs, and grain storage

Rural SA1s include one or more of the following:

• residential development with a density of less than 200 people 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

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

Where possible, SA1s are designed to contain, or aggregate to, whole officially recognised suburbs or rural localities. In urban areas, the suburbs usually consist of one or more SA1s.

In regional and remote areas, officially recognised localities are sometimes too small to satisfy SA1 design criteria. Smaller localities are grouped together based on their Local Government Area, the use of shared road networks, the use of shared community facilities, and landscape features such as a populated location within a valley.

SA1s are created in anticipation of development which is likely to occur before the date of the 2026 Census of Population and Housing.

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

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

Zero SA1s are designed to have no population. They are designed to represent large unpopulated areas that are not easily combined with surrounding populated SA1s.

They may include one or more of the following:

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

SA1s are not named.

SA1s are identified by an 11-digit fully hierarchical code, comprising a 1-digit State and Territory identifier, and Statistical Areas Level 1-4 identifiers. The SA1 identifier is a 2-digit code, assigned within an SA2.

An SA1 code is unique when it is preceded by the State or Territory identifier.

If an SA1 is discontinued, or changes significantly, the SA1 identifier is retired, and the next available unused identifier will be applied. Changes at higher level geographies within the structure may also result in a code change for the SA1. For example, if a new SA2 is created, existing SA1s will be allocated a new code to reflect the change in SA2 identifier. More information about identifying change, including code changes, is in Changes from the previous edition of the ASGS.