Edeirnion or Edeyrnion is an area of the county of Denbighshire and an ancient commote of medieval Wales in the cantref of Penllyn. According to tradition, it was named after its eponymous founder Edern or Edeyrn. It was included as a Welsh territory of Shropshire in the Domesday Book.

Edeirnion or Edeyrnion is an area of the county of Denbighshire and an ancient commote of medieval Wales in the cantref of Penllyn. According to tradition, it was named after its eponymous founder Edern or Edeyrn. It was included as a Welsh territory of Shropshire in the Domesday Book.