The 1st, 2nd and 3rd editions of the historic 25-inch O. S. maps, published in 1874, 1899, and 1912 respectively, all depict Llanarmon Mill as a working flour mill. The building still stands at the east end of the village, close to the bridge over the Afon Alyn. With two storeys and an attic and built of limestone rubble, it has been converted to a dwelling with the front elevation (facing north-east) raised to light the attic storey by three triple-light modern windows matching those on the first floor. Water was diverted from the Afon Alyn by a weir into a mill race 990 metres long, and the water wheel appears to have been on the north-east gable of the mill.
W J Crompton, RCAHMW, 21st March 2019.