List of urban areas in the United Kingdom

List of urban areas in the United Kingdom is a list of the most populous urban areas as at the 2011 census, as defined by the Office for National Statistics (ONS), although the basis for the sourced list (used for its ready availability of the data) is Citypopulation.de.

The detailed methodology of the process used by ONS in 2011 is set out in 2011 Built-up Areas – Methodology and Guidance, published in June 2013. In reporting the results of the 2011 UK census, ONS use the term "built-up area" rather than the term "urban area" used for previous censuses. However, it states that the criteria used to define "built-up area" are the same as those used previously, as follows:

the definition follows a ‘bricks and mortar’ approach, with areas defined as built-up land with a minimum area of 20 hectares (200,000 m²), while settlements within 200 metres of each other are linked. Built-up area sub-divisions are also identified to provide greater detail in the data, especially in the larger conurbations.

In reporting the 2001 census, ONS gave a clearer definition of the term "built-up" as follows:

This comprises permanent structures and the land on which they are situated, including land enclosed by or closely associated with such structures; transportation corridors such as roads, railways and canals which have built up land on one or both sides, or which link built-up sites which are less than 200 metres apart; transportation features such as airports and operational airfields, railway yards, motorway service areas and car parks; mine buildings, excluding mineral workings and quarries; and any area completely surrounded by builtup sites. Areas such as playing fields and golf courses are excluded unless completely surrounded by builtup sites...