"A hamlet in the parish of Llanarmon, Union of Ruthin, hundred of Yale, county of Denbigh; 4½ miles (E) from Ruthin; containing 681 inhabitants. ..... It is bounded on the western side by the lofty Clwydian mountains, which separate it from the Vale of Clwyd, and on the eastern by a range of hills, nearly equal in height, separating from Flintshire."
[ A Topographical Dictionary of Wales, 1833 & 1849, Samuel Lewis]
The new parish of Eryrys was formed by an Order in Council on 11 October 1861, from parts of the townships of Eryrys, Cyfnant, and Gwaunyffynnon, which had until then been in the parish of Llanarmon yn Iâl.