Cynllaith
{{Short description|Welsh medieval commote}}
{{Use dmy dates|date=April 2022}}
File:Wales.medieval.cymydau.jpg
Cynllaith or Cynllaeth was a commote ({{lang|cy|cwmwd}}) of north east Wales in the cantref of {{lang|cy|Swydd y Waun|italic=no}} (later Chirkland) which was once part of the Kingdom of Powys and later part of the smaller kingdom of Powys Fadog.{{cite book|last1=Rees|first1=William|title=An Historical Atlas of Wales from Early to Modern Times|date=1951|publisher=Faber & Faber}}
Cynllaith, or at least the part of it called Cynllaith Owain, was part of the inheritance of Owain Glyndŵr in 1370.{{cite journal|last1=Rees|first1=William|title=The Union of England and Wales|journal=Transactions of the Honourable Society of Cymmrodorion|date=1937|page=88}} The titles Baron of Glyndyfrdwy and Lord of Cynllaith Owain were used by the dispossessed former ruling family of Powys Fadog before Owain was proclaimed Prince of Wales in 1400.{{cite web|title=OWAIN GLYNDWR|url=https://biography.wales/article/s-OWAI-GLY-1354|website=Dictionary of Welsh Biography|publisher=National Library of Wales}}
The episode "Monk's Hood" of the Cadfael Chronicles includes a scene in a Welsh court in Llansilin within this commote.