List of built-up areas in Wales by population

The following is a list of built-up areas in Wales by population according to the 2021 and 2011 Census.

2021

Rank	Built-up Area	Population (2011 Census)	Notes
1	Cardiff (built-up area)	447,287^[2]	Includes Caerphilly/Pontypridd/Penarth
2	Newport (built-up area)	306,844^[3]	Includes Cwmbran/Pontypool/Blackwood
3	Swansea (built-up area)	300,352^[4]	Includes Neath/Port Talbot/Pontardawe/Ystradgynlais
4	Wrexham (built-up area)	65,692^[5]	Includes Rhostyllen/Gwersyllt/Brymbo
5	Tonypandy	62,545^[6]	Includes Treorchy/Porth
6	Bridgend	58,380^[7]	Includes Wild Mill/Tondu/Sarn
7	Barry	54,673^[8]	Includes Sully
8	Llanelli	49,591^[9]	Includes Llangennech
9	Rhyl/Prestatyn (built-up area)	46,267^[10]
10	Merthyr Tydfil	43,820^[11]	Includes Dowlais/Gellideg
11	Bay of Colwyn	34,284^[12]
12	Ebbw Vale/Brynmawr/Nantyglo	33,068^[13]
13	Aberdare	31,135^[14]
14	Flint	26,442^[15]	Includes Holywell/Bagillt
15	Rhosllanerchrugog	25,362^[16]
16	Ammanford	23,709^[17]
17	Church Village/Llantwit Fardre	23,277^[18]
18	Maesteg	21,001^[19]
19	Gorseinon	20,581^[20]
20	Ystrad Mynach	19,204^[21]
21	Aberystwyth	18,749^[22]
22	Kinmel Bay/Abergele	18,705^[23]
23	Bangor	17,988^[24]
24	Connah's Quay	16,774^[25]
25	Chepstow	16,169^[26]
26	Carmarthen	15,854^[27]
27	Porthcawl	15,672^[28]
28	Llandudno	15,371^[29]
29	Risca	14,958^[30]
30	Tredegar	14,855^[31]
31	Abergavenny	14,651^[32]
32	Haverfordwest	14,596^[33]
33	Llantrisant	14,422^[34]
34	Llantwit Major	14,384^[35]
35	Pyle	13,701^[36]
36	Milford Haven	13,582^[37]
37	Splott	13,261^[38]
38	Treharris	12,352^[39]
39	Bargoed	11,900^[40]
40	Holyhead	11,431^[41]