51.47°N -3.173°WThe Cardiff Built-up Area or Cardiff Urban Area is the name given to the urban area around Cardiff. The vast bulk of the population and area are contributed by Cardiff, which had a population of 335,145 at the 2011 census. The rest was made up by the towns of Penarth and Dinas Powys, connected to the south-west of the city along Cardiff Bay; as well as the South Wales Valleys towns of Caerphilly and Pontypridd. The total official population of this urban area was given to be 447,487 in 2011.[1] This was an increase of almost 37% on the 2001 population of 327,706. This was mainly due to Caerphilly and Pontypridd becoming part of the built-up area. The population of the Cardiff unitary authority (not co-terminous with the built-up area or the wider urban area) in 2001 was 305,353.[2] Cardiff Council estimated the population of the unitary authority at 317,500 in 2006; at the 2011 census it was 346,090.
According to the ONS definition the Cardiff Urban Area had the following subdivisions:
| Rank | Urban sub-area | Population | ||
|---|---|---|---|---|
| 2001 census | 2011 census | |||
| 1 | Cardiff | 292,150 | 335,145 | |
| 2 | Caerphilly | 41,402 | ||
| 3 | Pontypridd | 30,457 | ||
| 4 | Penarth | 23,245 | 27,226 | |
| 5 | Dinas Powys | 7,653 | 7,490 | |
| 6 | Taff's Well | 5,567 | ||
| Radyr | 4,658 | |||
| Total | 327,206 | 447,287 | ||
Notes: