UK Census Geography

Decennial population censuses are the most important source of population data for small geographical areas in the UK. Although population estimates and projections are produced more frequently, these generally relate to much larger areas. The geography of the census is designed to match the administrative organization of the country at the time of each census, and this set of geographical areas is used for many other purposes. In particular, the population and derived data (such as deprivation indicators) that can be produced for census areas are frequently used as the denominators for information from other sources.

Modern (since 1971) census geographies are hierarchical subdivisions of UK local government areas of various types, down to sub-authority areas such as wards or postcode sectors and finally into lower-level units created specifically for census purposes. Unfortunately, census geography is not consistent between successive censuses or between the different countries which make up the UK and the terminology and precise definitions of all the areas below the country level can vary. Each census geography is only a 'snapshot' of a continually changing administrative geography (local government reorganization and redrawing of electoral wards by the Boundary Commission) and must also incorporate large-scale population change such as new areas of housing.