In 1870-72, John Marius Wilson's Imperial Gazetteer of England and Wales described Llandyrnog like this:
LLANDYRNOG, a village, a parish, and a sub-district, in Ruthin district, Denbigh. The village stands about a mile from the river Clwyd, under Bryn-y-Cloddian, 3¼ miles E of Denbigh r. station; and has a post office under Denbigh.The parish comprises the townships of Ystrad, Banker, Caerfedwin, Cwmdylluan, Llan-Rhiwbebyl, and Speddyd. Acres, 3,223. Real property, £4,289. Pop., 655. Houses, 140. The property is divided among a few. Glanywern is the seat of Lieut. Col. Madocks. ...
Vron Iw was the seat of the Madocks family, and is now a farm-house. An ancient British camp is on Bryn y-Cloddian. The living is a rectory in the diocese of St. Asaph. Value, £666. * Patron, the Bishop of St. David's. The church is dedicated to St. Tyrnog, and is good. Charities, £15.--The subdistrict contains also two other parishes, and part of another. Acres, 10,068. Pop., 1,826. Houses, 406.
A Vision of Britain through Time includes a large library of local statistics for administrative units. For the best overall sense of how the area containing Llandyrnog has changed, please see our redistricted information for the modern district of Denbighshire. More detailed statistical data are available under Units and statistics, which includes both administrative units covering Llandyrnog and units named after it.
GB Historical GIS / University of Portsmouth, History of Llandyrnog in Denbighshire | Map and description, A Vision of Britain through Time.
Date accessed: 25th February 2017
Click here for more detailed advice on finding places within A Vision of Britain through Time, and maybe some references to other places called "Llandyrnog".