"The village, which has arisen within the present century, and greatly increased since the discovery of some rich mines in the vicinity, is pleasantly situated in a fertile district; and the elevated ground adjacent to it commands a fine prospect of the surrounding scenery which, on the north, east and south expands into an almost boundless view. .... At a small distance from the village rises the Halkin mountain, rich in mineral treasures. It extends into the parishes of Northop, Ysceiviog, and Holywell, and forms one continued series of excavations made in search of lead-ore, of which no part of the principality has been more productive."
[ A Topographical Dictionary of Wales, S. Lewis, 1849]
Halkyn is one of the "ancient parishes" of Flintshire, comprising the townships of Hendrefigillt, Lygan y Llan and Lygan y Wern. On 27 June 1848, the township of Hendrefigillt went to the new parish of Rhesycae. Archdeacon Thomas (1911) states that on 31 March 1865, part of the township of Lygan y Llan went to the new parish of Rhydymwyn, but from a study of the township boundaries, that seems to be unlikely.