This is a list of principal areas of Wales ordered by population. The figures are mid-year estimates for 2010 from the Office for National Statistics.
| Rank | District | Population | Style |
|---|---|---|---|
| 1 | Cardiff | 341,100 | City and county |
| 2 | Rhondda Cynon Taff | 234,300 | County borough |
| 3 | Swansea | 232,500 | City and county |
| 4 | Carmarthenshire | 180,700 | County |
| 5 | Caerphilly | 173,100 | County borough |
| 6 | Flintshire | 149,700 | County |
| 7 | Newport | 141,300 | City and county |
| 8 | Neath Port Talbot | 137,400 | County borough |
| 9 | Bridgend | 134,600 | County borough |
| 10 | Wrexham | 133,600 | County borough |
| 11 | Powys | 131,300 | County |
| 12 | Vale of Glamorgan | 125,000 | County borough |
| 13 | Gwynedd | 119,000 | County |
| 14 | Pembrokeshire | 117,100 | County |
| 15 | Conwy | 110,900 | County borough |
| 16 | Denbighshire | 96,700 | County |
| 17 | Torfaen | 90,500 | County borough |
| 18 | Monmouthshire | 88,100 | County |
| 19 | Ceredigion | 76,900 | County |
| 20 | Anglesey | 68,600 | County |
| 21 | Blaenau Gwent | 68,400 | County borough |
| 22 | Merthyr Tydfil | 55,700 | County borough |
"Table 8a Mid-2010 Population Estimates: Selected age groups for local authorities in the United Kingdom; estimated resident population.". Population Estimates for UK, England and Wales, Scotland and Northern Ireland, Mid-2010. Office for National Statistics. 3 June 2011. http://www.ons.gov.uk/ons/publications/re-reference-tables.html?edition=tcm%3A77-231847. Retrieved 1 October 2011.