The Swansea Urban Area or Swansea Built-up Area is an area of land in south Wales, defined by the Office for National Statistics for population monitoring purposes. It is an urban conurbation and is not coterminous with the City and County of Swansea. It consists of the urban area centred on Swansea city centre; the Swansea Valley including Clydach, Ystradgynlais and Pontardawe; and includes Neath and Port Talbot which lay outside the county boundaries, but excludes the urban area of Gorseinon within the county boundaries.
The total population of the area in 2011 was 300,352 making it the 24th largest conurbation in England and Wales and the 3rd largest in Wales. This was an increase of 11% from the 2001 figure of 270,506. Most of the increase was due to Ystradgynlais, Gowerton, Upper Killay and Glais becoming part of the urban area.
Swansea Urban Area Wikipedia
The ONS provides sub-division statistics for the Swansea Urban Area
Notes:Gowerton was included under the Swansea subdivision for the 2001 census.
Ystradgynlais was not part of the Swansea urban area until the 2011 census