Statistical geographies

Output Areas (OAs)

Output Areas (OAs) are the lowest level of geographical area for census statistics and were first created following the 2001 Census. Using Census 2021 data, some changes were made to 2011 OAs as a result of population and household changes since 2011. Additionally, around 200 OA boundaries were selectively realigned to ward boundaries.

2011 OAs that were still made up of between 40 and 250 households and had a usually resident population between 100 and 625 persons did not change. Otherwise, new 2021 OAs were created by merging or splitting 2011 OAs to make sure they fitted within the population and household thresholds of the unchanged 2011 OAs.

There are some exceptions where OAs may have more than 625 people, for example, where there is a large prison.

Outputs from Census 2021 are for 2021 OAs and are made up of unchanged 2011 OAs and new 2021 OAs.

The 2021 OAs are available as boundary sets, and lookup files, which can be downloaded from the Open Geography portal.

Lower layer Super Output Areas (LSOAs)

Lower layer Super Output Areas (LSOAs) are made up of groups of Output Areas (OAs), usually four or five. They comprise between 400 and 1,200 households and have a usually resident population between 1,000 and 3,000 persons.

Using Census 2021 data, some changes were made to 2011 LSOAs as a result of population and household changes since 2011. New 2021 LSOAs were created by merging or splitting 2011 LSOAs to ensure that population and household thresholds were met.

Outputs from Census 2021 are for 2021 LSOAs and are made up of unchanged 2011 LSOAs and new 2021 LSOAs.

There are 33,755 LSOAs in England and 1,917 in Wales. The 2021 LSOAs are available as boundary sets, names and codes, and lookup files, which can be downloaded from the Open Geography portal.

Middle layer Super Output Areas (MSOAs)

Middle layer Super Output Areas (MSOAs) are made up of groups of Lower layer Super Output Areas (LSOAs), usually four or five. They comprise between 2,000 and 6,000 households and have a usually resident population between 5,000 and 15,000 persons. MSOAs fit within local authorities.

Outputs from Census 2021 are for 2021 MSOAs and are made up of unchanged 2011 MSOAs and new 2021 MSOAs.

There are 6,856 MSOAs in England and 408 in Wales. The 2021 MSOAs are available as boundary sets, names and codes, and lookup files, which can be downloaded from the Open Geography portal.

OAs, LSOAs and MSOAs make up the different levels of the census statistical geographies.

Scotland's census took place a year after the rest of the UK, in March 2022. Read about Scotland's output plans on Scotland's census website.

Read about the Northern Ireland Statistics and Research Agency (NISRA) plans for releasing Census 2021 statistics.