Edeirnion

Edeirnion or Edeyrnion is an area of the county of Denbighshire and an ancient commote of medieval Wales in the cantref of Penllyn.

These rumbling border disputes caused a great deal of friction between the two realms.

This continuing dispute and the appeal by Llywelyn ap Gruffudd to Edward I of England to see the resolution of this dispute settled by Welsh Law was one of the reasons the principalities in the north of Wales were unable to unite in opposition to English hegemony and was a contributing factor to the final war between the Principality of Wales and England, which ultimately saw the end of Welsh independence.

Edeirnion still exists as a bro, or region, in Denbighshire, located around Corwen and near the Berwyn Range.

It consisted of six civil parishes and covered 47,460 acres (192.1 km2); it continued in existence until 1974, when it was abolished, as a result of the Local Government Act 1972, becoming part of the Glyndŵr District of Clwyd.