Mesh block

What a mesh block is

Mesh blocks are the building blocks of the ASGS. Each is a single continuous area whose boundaries generally follow road centrelines and natural features such as water, parkland and mountain ranges, and the ABS designs each one, where possible, to hold 30 to 60 dwellings, a size intended partly to protect confidential information. High-density apartment blocks can exceed 60 dwellings, and some rural mesh blocks hold fewer so that they match an officially recognised locality.

There are 374,917 mesh blocks in the 2026 boundaries (ASGS Edition 4), up from 368,286 in 2021, and 114 of them are non-spatial special purpose codes for people who can't be placed on a map. Each has an 11-digit code made of a one-digit state or territory code and a 10-digit identifier. When a 2021 mesh block was split or substantially redesigned for 2026, the ABS retired its code and gave the new mesh blocks codes that hadn't been used before.

Land use

The ABS tags each mesh block with one of ten land-use categories, chosen to separate residential areas from commercial and industrial ones: Residential, Commercial, Industrial, Parkland, Education, Hospital/Medical, Transport, Primary Production, Water and Other, which covers mixed use and land that is hard to classify. Commercial, Industrial, Parkland, Transport and Water mesh blocks are designed to hold no population where possible, so airports, industrial sites and large shopping complexes sit in mesh blocks of their own, and the ABS keeps whole facilities such as hospitals, universities and apartment buildings inside one mesh block where it can.

What's published for mesh blocks

Because of confidentiality restrictions, the ABS releases two Census figures for mesh blocks: the number of usual residents and the number of dwellings. The 2021 counts were released on 28 June 2022. Residents are counted where they usually live, which may differ from where they were on Census night, and the dwelling count includes unoccupied private dwellings except those in caravan parks, marinas and manufactured home estates. Age, income, rent and every other Census topic start at SA1 level.

Building other areas from mesh blocks

Whole mesh blocks make up each SA1, and through SA1s every level of the main structure up to GCCSAs and states. The ABS also uses mesh blocks to approximate areas defined by other bodies, the Non ABS Structures: Local Government Areas, Suburbs and Localities, Postal Areas, state and Commonwealth electoral divisions and Destination Zones. For Postal Areas, each mesh block is generally allocated to the postcode holding the largest share of its population, which is why their edges can differ from Australia Post's. The ABS allocation file lists, for each mesh block, the SA1, SA2, SA3, SA4, GCCSA and state it belongs to, with its area in square kilometres.

Mesh blocks also link addresses to ABS boundaries. G-NAF gives each address a mesh block code where one can be identified, so an address matched by geocoding can be placed in any ASGS area.

Their counts are also a basis for apportioning. Where a custom boundary such as a catchment cuts through an SA1, the mesh blocks inside show where that SA1's residents and dwellings are, which is a finer guide to splitting its figures than land area alone (see area weighting). The ABS used mesh block counts in a similar way for its 2011 correspondences, which were weighted by a population grid built from 2006 Collection District or 2011 mesh block counts.

Mesh blocks and Censible

Censible uses mesh blocks to work out where an SA1's residents live when a catchment or drawn area cuts through it. Each mesh block counts as a single point, fully in or out of the area, and the 2026 mesh blocks use the 2021 resident counts carried onto them with the ABS's mesh block correspondence, because counts for the 2026 mesh blocks won't exist until the 2026 Census. Census figures in Censible start at SA1, as the ABS's do.

Sources: ABS, ASGS Edition 4, Mesh Blocks; ABS, Census Mesh Block Counts, 2021; ABS, ASGS Edition 4, Changes from the previous edition.