Ystradgynlais
| Ystradgynlais | |
|---|---|
| Junction at Heol Eglwys | |
| Location within Powys | |
| Population | 8,092 (2011) | 
| OS grid reference | SN793106 | 
| Community | 
 | 
| Principal area | |
| Preserved county | 
 | 
| Country | Wales | 
| Sovereign state | United Kingdom | 
| Post town | Swansea | 
| Postcode district | SA9 | 
| Dialling code | 01639 | 
| Police | Dyfed-Powys | 
| Fire | Mid and West Wales | 
| Ambulance | Welsh | 
| UK Parliament | |
| Senedd Cymru – Welsh Parliament | |
Ystradgynlais (English: /ˌʌstrədˈɡʌnlaɪs/; Welsh: [ˌəstradˈɡənlais] ⓘ) is a town in southwest Powys, Wales. It is located on the River Tawe, and was within the boundaries of the former county of Brecknockshire. The town has a high proportion of Welsh language-speakers. The community includes Cwmtwrch, Abercraf and Cwmgiedd, with a population of 8,092 in the 2011 census; it is the second-largest town in Powys. It forms part of the Swansea Urban Area where the Ystradgynlais subdivision has a population of 10,248.