"A parish in the Union of Ruthin, partly in the hundred of Isaled, but chiefly in that of Ruthin, county of Denbigh; 3 miles (NNW) from Ruthin, containing 784 inhabitants. This parish, which is situated on the river Clwyd, and is intersected by the turnpike road leading from Ruthin to Denbigh, extends nearly eight miles in length, and one mile and a half in mean breadth. ..... The surrounding scenery is pleasingly diversified, and the views from the higher grounds, extending over the adjacent country, embrace some interesting features." [A Topographical Dictionary of Wales, 1833 & 1849, Samuel Lewis]
The ancient parish of Llanynys consisted of the townships of Bachymbyd ( or Machymbyd), Bontuchel, Bryncaredig, Ffiddoedd, Maesmaencymro, Rhydonnen, Trefechan, Trefor ( or Cefn Trefor), Treganol ( or Fachlwyd), Tre'r Parc, and Ysgeibion ( or Esgeibion).
It was the mother parish of Cyffylliog until 26 January 1874, when the townships of Bontuchel, Trefor, Treganol, Ffiddoedd and Tre'r Parc were transferred from Llanynys to the new parish of Cyffylliog. However, to all intents and purposes, Cyffylliog had already functioned as a separate parish for many years.